diff --git a/contracts/StorageContract.sol b/contracts/StorageContract.sol
index 8212c5d..fd77b98 100644
--- a/contracts/StorageContract.sol
+++ b/contracts/StorageContract.sol
@@ -21,6 +21,7 @@ contract StorageContract {
               uint _price,
               uint _proofPeriod,
               uint _proofTimeout,
+              uint _bidExpiry,
               address _host,
               bytes memory requestSignature,
               bytes memory bidSignature)
@@ -32,10 +33,11 @@ contract StorageContract {
       _proofPeriod,
       _proofTimeout
     );
-    bytes32 bidHash = hashBid(requestHash, _price);
+    bytes32 bidHash = hashBid(requestHash, _bidExpiry, _price);
     checkSignature(requestSignature, requestHash, msg.sender);
     checkSignature(bidSignature, bidHash, _host);
     checkProofTimeout(_proofTimeout);
+    checkBidExpiry(_bidExpiry);
     duration = _duration;
     size = _size;
     price = _price;
@@ -68,13 +70,14 @@ contract StorageContract {
   }
 
   // Creates hash for a storage bid that can be used to check its signature.
-  function hashBid(bytes32 requestHash, uint _price)
+  function hashBid(bytes32 requestHash, uint _expiry, uint _price)
     internal pure
     returns (bytes32)
   {
     return keccak256(abi.encodePacked(
       "[dagger.bid.v1]",
       requestHash,
+      _expiry,
       _price
     ));
   }
@@ -95,6 +98,10 @@ contract StorageContract {
     require(timeout <= 128, "Invalid proof timeout, needs to be <= 128");
   }
 
+  function checkBidExpiry(uint expiry) internal view {
+    require(expiry > block.timestamp, "Bid expired");
+  }
+
   // Check whether a proof is required at the time of the block with the
   // specified block number. A proof has to be submitted within the proof
   // timeout for it to be valid. Whether a proof is required is determined
diff --git a/test/StorageContract.test.js b/test/StorageContract.test.js
index 18f84cb..7377ee5 100644
--- a/test/StorageContract.test.js
+++ b/test/StorageContract.test.js
@@ -13,6 +13,7 @@ describe("Storage Contract", function () {
 
   var StorageContract
   var client, host
+  var bidExpiry
   var requestHash, bidHash
   var contract
 
@@ -26,7 +27,8 @@ describe("Storage Contract", function () {
       proofPeriod,
       proofTimeout
     )
-    bidHash = hashBid(requestHash, price)
+    bidExpiry = Math.round(Date.now() / 1000) + 60 * 60 // 1 hour from now
+    bidHash = hashBid(requestHash, bidExpiry, price)
   })
 
   describe("when properly instantiated", function () {
@@ -39,6 +41,7 @@ describe("Storage Contract", function () {
         price,
         proofPeriod,
         proofTimeout,
+        bidExpiry,
         await host.getAddress(),
         await sign(client, requestHash),
         await sign(host, bidHash)
@@ -90,6 +93,7 @@ describe("Storage Contract", function () {
       price,
       proofPeriod,
       proofTimeout,
+      bidExpiry,
       await host.getAddress(),
       invalidSignature,
       await sign(host, bidHash)
@@ -97,7 +101,8 @@ describe("Storage Contract", function () {
   })
 
   it("cannot be created when host signature is invalid", async function () {
-    let invalidSignature = await sign(host, hashBid(requestHash, price - 1))
+    let invalidBid = hashBid(requestHash, bidExpiry, price - 1)
+    let invalidSignature = await sign(host, invalidBid)
     await expect(StorageContract.deploy(
       duration,
       size,
@@ -105,6 +110,7 @@ describe("Storage Contract", function () {
       price,
       proofPeriod,
       proofTimeout,
+      bidExpiry,
       await host.getAddress(),
       await sign(client, requestHash),
       invalidSignature
@@ -120,7 +126,7 @@ describe("Storage Contract", function () {
       proofPeriod,
       invalidTimeout
     )
-    bidHash = hashBid(requestHash, price)
+    bidHash = hashBid(requestHash, bidExpiry, price)
     await expect(StorageContract.deploy(
       duration,
       size,
@@ -128,12 +134,30 @@ describe("Storage Contract", function () {
       price,
       proofPeriod,
       invalidTimeout,
+      bidExpiry,
       await host.getAddress(),
       await sign(client, requestHash),
       await sign(host, bidHash),
     )).to.be.revertedWith("Invalid proof timeout")
   })
 
+  it("cannot be created when bid has expired", async function () {
+    let expired = Math.round(Date.now() / 1000) - 1 // 1 second ago
+    let bidHash = hashBid(requestHash, expired, price)
+    await expect(StorageContract.deploy(
+      duration,
+      size,
+      contentHash,
+      price,
+      proofPeriod,
+      proofTimeout,
+      expired,
+      await host.getAddress(),
+      await sign(client, requestHash),
+      await sign(host, bidHash),
+    )).to.be.revertedWith("Bid expired")
+  })
+
   describe("proofs", function () {
 
     async function mineBlock() {
@@ -158,6 +182,7 @@ describe("Storage Contract", function () {
         price,
         proofPeriod,
         proofTimeout,
+        bidExpiry,
         await host.getAddress(),
         await sign(client, requestHash),
         await sign(host, bidHash)
@@ -239,6 +264,4 @@ describe("Storage Contract", function () {
 // TODO: only allow proofs after start of contract
 // TODO: payout
 // TODO: stake
-// TODO: request expiration
-// TODO: bid expiration
 // TODO: multiple hosts in single contract
diff --git a/test/marketplace.js b/test/marketplace.js
index 2aad7cc..1af8452 100644
--- a/test/marketplace.js
+++ b/test/marketplace.js
@@ -7,10 +7,10 @@ function hashRequest(duration, size, hash, proofPeriod, proofTimeout) {
   )
 }
 
-function hashBid(requestHash, price) {
+function hashBid(requestHash, expiry, price) {
   return ethers.utils.solidityKeccak256(
-    ["string", "bytes32", "uint"],
-    ["[dagger.bid.v1]", requestHash, price]
+    ["string", "bytes32", "uint", "uint"],
+    ["[dagger.bid.v1]", requestHash, expiry, price]
   )
 }