diff --git a/contracts/Marketplace.sol b/contracts/Marketplace.sol
index 999a198..9e92634 100644
--- a/contracts/Marketplace.sol
+++ b/contracts/Marketplace.sol
@@ -94,7 +94,7 @@ contract Marketplace is Collateral, Proofs {
     slot.requestId = requestId;
     RequestContext storage context = _context(requestId);
     context.slotsFilled += 1;
-    activeSlots[request.client].add(SlotId.unwrap(slotId));
+    activeSlots[slot.host].add(SlotId.unwrap(slotId));
     emit SlotFilled(requestId, slotIndex, slotId);
     if (context.slotsFilled == request.ask.slots) {
       context.state = RequestState.Started;
@@ -108,6 +108,7 @@ contract Marketplace is Collateral, Proofs {
     internal
     slotMustAcceptProofs(slotId)
     marketplaceInvariant
+    // TODO: restrict senders that can call this function
   {
     Slot storage slot = _slot(slotId);
     RequestId requestId = slot.requestId;
@@ -120,6 +121,7 @@ contract Marketplace is Collateral, Proofs {
 
     _unexpectProofs(_toProofId(slotId));
 
+    activeSlots[slot.host].remove(SlotId.unwrap(slotId));
     slot.host = address(0);
     slot.requestId = RequestId.wrap(0);
     context.slotsFilled -= 1;
@@ -135,6 +137,9 @@ contract Marketplace is Collateral, Proofs {
       _setProofEnd(_toEndId(requestId), block.timestamp - 1);
       context.endsAt = block.timestamp - 1;
       activeRequests[request.client].remove(RequestId.unwrap(requestId));
+      // NOTE: not removing any remaining active slots for the host as listing
+      // values of enumerable set could be too expensive (copies from storage to
+      // memory)
       emit RequestFailed(requestId);
 
       // TODO: burn all remaining slot collateral (note: slot collateral not
@@ -155,6 +160,7 @@ contract Marketplace is Collateral, Proofs {
     SlotId slotId = _toSlotId(requestId, slotIndex);
     Slot storage slot = _slot(slotId);
     require(!slot.hostPaid, "Already paid");
+    activeSlots[slot.host].remove(SlotId.unwrap(slotId));
     uint256 amount = pricePerSlot(requests[requestId]);
     funds.sent += amount;
     funds.balance -= amount;
diff --git a/test/Marketplace.test.js b/test/Marketplace.test.js
index ff3bfa8..7d50c1b 100644
--- a/test/Marketplace.test.js
+++ b/test/Marketplace.test.js
@@ -731,4 +731,47 @@ describe("Marketplace", function () {
       expect(await marketplace.myRequests()).to.deep.equal([])
     })
   })
+
+  describe("list of active slots", function () {
+    beforeEach(async function () {
+      switchAccount(client)
+      await token.approve(marketplace.address, price(request))
+      await marketplace.requestStorage(request)
+      switchAccount(host)
+      await token.approve(marketplace.address, collateral)
+      await marketplace.deposit(collateral)
+    })
+
+    it("adds slot to list when filling slot", async function () {
+      await marketplace.fillSlot(slot.request, slot.index, proof)
+      let slot1 = { ...slot, index: slot.index + 1 }
+      await marketplace.fillSlot(slot.request, slot1.index, proof)
+      expect(await marketplace.mySlots()).to.deep.equal([
+        slotId(slot),
+        slotId(slot1),
+      ])
+    })
+
+    it("removes request from list when slot is freed", async function () {
+      await marketplace.fillSlot(slot.request, slot.index, proof)
+      let slot1 = { ...slot, index: slot.index + 1 }
+      await marketplace.fillSlot(slot.request, slot1.index, proof)
+      await marketplace.freeSlot(slotId(slot))
+      expect(await marketplace.mySlots()).to.deep.equal([slotId(slot1)])
+    })
+
+    it("removes all slots from list when request fails", async function () {
+      await waitUntilStarted(marketplace, request, proof)
+      await waitUntilFailed(marketplace, request, slot)
+      let expectedLength = request.ask.slots - (request.ask.maxSlotLoss + 1)
+      expect((await marketplace.mySlots()).length).to.equal(expectedLength)
+    })
+
+    it("removes slots from list when request finishes", async function () {
+      await waitUntilStarted(marketplace, request, proof)
+      await waitUntilFinished(marketplace, requestId(request))
+      await marketplace.payoutSlot(slot.request, slot.index)
+      expect(await marketplace.mySlots()).to.not.contain(slotId(slot))
+    })
+  })
 })