diff --git a/src/IndexRegistry.sol b/src/IndexRegistry.sol
index 26dc8bbf..ba3cfdba 100644
--- a/src/IndexRegistry.sol
+++ b/src/IndexRegistry.sol
@@ -89,7 +89,7 @@ contract IndexRegistry is IndexRegistryStorage {
     function initializeQuorum(
         uint8 quorumNumber
     ) public virtual onlyRegistryCoordinator {
-        require(_operatorCountHistory[quorumNumber].length == 0, QuorumDoesNotExist());
+        require(_operatorCountHistory[quorumNumber].length == 0, QuorumAlreadyExists());
 
         _operatorCountHistory[quorumNumber].push(
             QuorumUpdate({numOperators: 0, fromBlockNumber: uint32(block.number)})
diff --git a/src/interfaces/IIndexRegistry.sol b/src/interfaces/IIndexRegistry.sol
index c4d5d997..9464099f 100644
--- a/src/interfaces/IIndexRegistry.sol
+++ b/src/interfaces/IIndexRegistry.sol
@@ -6,6 +6,8 @@ interface IIndexRegistryErrors {
     error OnlyRegistryCoordinator();
     /// @notice Thrown when attempting to query a quorum that has no history.
     error QuorumDoesNotExist();
+    /// @notice Thrown when attempting to initialize a quorum that already exists.
+    error QuorumAlreadyExists();
     /// @notice Thrown when attempting to look up an operator that does not exist at the specified block number.
     error OperatorIdDoesNotExist();
 }