diff --git a/contracts/StatusMap.sol b/contracts/StatusMap.sol
index 1cdf8bb..d3fecb1 100644
--- a/contracts/StatusMap.sol
+++ b/contracts/StatusMap.sol
@@ -27,7 +27,7 @@ contract StatusMap {
     /**
      * @dev Sets the bit at `index` to the boolean `value` for the account `account`.
      */
-    function _overwriteStatusTo(address account, uint256 index, bool value) internal {
+    function _overwriteStatusTo(address account, uint8 index, bool value) internal {
         if (value) {
             _assignStatus(account, index);
         } else {
@@ -52,7 +52,7 @@ contract StatusMap {
     /**
      * @dev Sets the bit at `index` to 1 for the account `account`.
      */
-    function _assignStatus(address account, uint256 index) internal {
+    function _assignStatus(address account, uint8 index) internal {
         uint256 mask = 1 << (index);
         statusesByAccount[account] |= mask;
     }
@@ -67,7 +67,7 @@ contract StatusMap {
     /**
      * @dev Sets the bit at `index` to 0 for the account `account`.
      */
-    function _unassignStatus(address account, uint256 index) internal {
+    function _unassignStatus(address account, uint8 index) internal {
         uint256 mask = 1 << index;
         statusesByAccount[account] &= ~mask;
     }
diff --git a/contracts/mock/MockStatusMap.sol b/contracts/mock/MockStatusMap.sol
index 6cd7400..d7b4ca8 100644
--- a/contracts/mock/MockStatusMap.sol
+++ b/contracts/mock/MockStatusMap.sol
@@ -12,7 +12,7 @@ contract MockStatusMap is StatusMap {
         return _areStatusesSet(account, mask);
     }
 
-    function overwriteStatusTo(address account, uint256 index, bool value) public {
+    function overwriteStatusTo(address account, uint8 index, bool value) public {
         _overwriteStatusTo(account, index, value);
     }
 
@@ -20,11 +20,11 @@ contract MockStatusMap is StatusMap {
         _assignMultipleStatuses(account, indicesMask);
     }
 
-    function assignStatus(address account, uint256 index) public {
+    function assignStatus(address account, uint8 index) public {
         _assignStatus(account, index);
     }
 
-    function unassignStatus(address account, uint256 index) public {
+    function unassignStatus(address account, uint8 index) public {
         _unassignStatus(account, index);
     }
 }