diff --git a/ethereumj-core/src/main/java/org/ethereum/vm/Program.java b/ethereumj-core/src/main/java/org/ethereum/vm/Program.java
index 0234fac6..554a19ad 100644
--- a/ethereumj-core/src/main/java/org/ethereum/vm/Program.java
+++ b/ethereumj-core/src/main/java/org/ethereum/vm/Program.java
@@ -213,7 +213,7 @@ public class Program {
 
         allocateMemory(offset, size);
         byte[] chunk;
-        if (memory != null)
+        if (memory != null && size != 0)
         	chunk = Arrays.copyOfRange(memory.array(), offset, offset+size);
         else
         	chunk = new byte[size];
diff --git a/ethereumj-core/src/test/java/org/ethereum/vm/ProgramMemoryTest.java b/ethereumj-core/src/test/java/org/ethereum/vm/ProgramMemoryTest.java
index f8eb7bc9..03184fdf 100644
--- a/ethereumj-core/src/test/java/org/ethereum/vm/ProgramMemoryTest.java
+++ b/ethereumj-core/src/test/java/org/ethereum/vm/ProgramMemoryTest.java
@@ -40,18 +40,29 @@ public class ProgramMemoryTest {
 	}
 
 	@Test
-	@Ignore
-	public void testMemoryChunk() {
-		fail("Not yet implemented");
+	public void testMemoryChunk1() {
+		program.memory = ByteBuffer.allocate(64);
+		int offset = 128;
+		int size = 32;
+		program.memoryChunk(offset, size);
+		assertEquals(160, program.getMemSize());
+	}
+	
+	@Test // size 0 doesn't increate memory
+	public void testMemoryChunk2() {
+		program.memory = ByteBuffer.allocate(64);
+		int offset = 96;
+		int size = 0;
+		program.memoryChunk(offset, size);
+		assertEquals(64, program.getMemSize());
 	}
 
 	@Test
 	public void testAllocateMemory1() {
 
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 32;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -61,10 +72,9 @@ public class ProgramMemoryTest {
 
 		// memory.limit() > offset, == size
 		// memory.limit() < offset + size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 32;
 		int size = 64;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -73,10 +83,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory3() {
 
 		// memory.limit() > offset, > size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 0;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -84,10 +93,9 @@ public class ProgramMemoryTest {
 	@Test
 	public void testAllocateMemory4() {
 
-		memory = ByteBuffer.allocate(64);;
+		program.memory = ByteBuffer.allocate(64);;
 		int offset = 0;
 		int size = 64;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -95,10 +103,9 @@ public class ProgramMemoryTest {
 	@Test
 	public void testAllocateMemory5() {
 
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 0;
 		int size = 0;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -107,10 +114,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory6() {
 
 		// memory.limit() == offset, > size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 64;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -119,10 +125,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory7() {
 
 		// memory.limit() == offset - size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 96;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(128, program.getMemSize());
 	}
@@ -130,10 +135,9 @@ public class ProgramMemoryTest {
 	@Test
 	public void testAllocateMemory8() {
 
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 0;
 		int size = 96;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -143,10 +147,9 @@ public class ProgramMemoryTest {
 
 		// memory.limit() < offset, > size
 		// memory.limit() < offset - size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 96;
 		int size = 0;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -160,7 +163,6 @@ public class ProgramMemoryTest {
 		// memory = null, offset > size
 		int offset = 32;
 		int size = 0;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(0, program.getMemSize());
 	}
@@ -171,7 +173,6 @@ public class ProgramMemoryTest {
 		// memory = null, offset < size
 		int offset = 0;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(32, program.getMemSize());
 	}
@@ -180,10 +181,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory12() {
 
 		// memory.limit() < offset, < size
-		memory = ByteBuffer.allocate(32);
+		program.memory = ByteBuffer.allocate(32);
 		int offset = 64;
 		int size = 96;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(160, program.getMemSize());
 	}
@@ -192,10 +192,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory13() {
 
 		// memory.limit() > offset, < size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 32;
 		int size = 128;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(160, program.getMemSize());
 	}
@@ -204,10 +203,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory14() {
 
 		// memory.limit() < offset, == size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 96;
 		int size = 64;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(160, program.getMemSize());
 	}
@@ -216,10 +214,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory15() {
 
 		// memory.limit() == offset, < size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 64;
 		int size = 96;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(160, program.getMemSize());
 	}
@@ -229,10 +226,9 @@ public class ProgramMemoryTest {
 
 		// memory.limit() == offset, == size
 		// memory.limit() > offset - size
-		memory = ByteBuffer.allocate(64);
+		program.memory = ByteBuffer.allocate(64);
 		int offset = 64;
 		int size = 64;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(128, program.getMemSize());
 	}
@@ -241,10 +237,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemory17() {
 
 		// memory.limit() > offset + size
-		memory = ByteBuffer.allocate(96);
+		program.memory = ByteBuffer.allocate(96);
 		int offset = 32;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -253,10 +248,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded1() {
 
 		// memory unrounded 
-		memory = ByteBuffer.allocate(16);
+		program.memory = ByteBuffer.allocate(16);
 		int offset = 64;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -265,10 +259,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded2() {
 
 		// offset unrounded 
-		memory = ByteBuffer.allocate(32);
+		program.memory = ByteBuffer.allocate(32);
 		int offset = 16;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -277,10 +270,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded3() {
 
 		// size unrounded 
-		memory = ByteBuffer.allocate(32);
+		program.memory = ByteBuffer.allocate(32);
 		int offset = 64;
 		int size = 16;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(96, program.getMemSize());
 	}
@@ -289,10 +281,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded4() {
 
 		// memory + offset unrounded 
-		memory = ByteBuffer.allocate(16);
+		program.memory = ByteBuffer.allocate(16);
 		int offset = 16;
 		int size = 32;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64	, program.getMemSize());
 	}
@@ -301,10 +292,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded5() {
 
 		// memory + size unrounded 
-		memory = ByteBuffer.allocate(16);
+		program.memory = ByteBuffer.allocate(16);
 		int offset = 32;
 		int size = 16;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(64, program.getMemSize());
 	}
@@ -313,10 +303,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded6() {
 
 		// offset + size unrounded 
-		memory = ByteBuffer.allocate(32);
+		program.memory = ByteBuffer.allocate(32);
 		int offset = 16;
 		int size = 16;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(32, program.getMemSize());
 	}
@@ -325,10 +314,9 @@ public class ProgramMemoryTest {
 	public void testAllocateMemoryUnrounded7() {
 
 		// memory + offset + size unrounded 
-		memory = ByteBuffer.allocate(16);
+		program.memory = ByteBuffer.allocate(16);
 		int offset = 16;
 		int size = 16;
-		program.memory = memory;
 		program.allocateMemory(offset, size);
 		assertEquals(32,program.getMemSize());
 	}