diff --git a/src/components/MemberOf/MemberOfHbacRules.tsx b/src/components/MemberOf/MemberOfHbacRules.tsx
index 82a37ad4..1395762b 100644
--- a/src/components/MemberOf/MemberOfHbacRules.tsx
+++ b/src/components/MemberOf/MemberOfHbacRules.tsx
@@ -6,12 +6,19 @@ import { User, HBACRule } from "src/utils/datatypes/globalDataTypes";
 // Components
 import MemberOfToolbar, { MembershipDirection } from "./MemberOfToolbar";
 import MemberOfHbacRulesTable from "./MemberOfTableHbacRules";
+import MemberOfAddModal, { AvailableItems } from "./MemberOfAddModal";
 // Hooks
 import useAlerts from "src/hooks/useAlerts";
 // RPC
-import { useGetHbacRulesInfoByNameQuery } from "src/services/rpc";
+import {
+  ErrorResult,
+  useAddToHbacRulesMutation,
+  useGetHbacRulesInfoByNameQuery,
+  useGettingHbacRulesQuery,
+} from "src/services/rpc";
 // Utils
 import { API_VERSION_BACKUP, paginate } from "src/utils/utils";
+import { apiToHBACRule } from "src/utils/hbacRulesUtils";
 
 interface MemberOfHbacRulesProps {
   user: Partial<User>;
@@ -103,10 +110,103 @@ const MemberOfHbacRules = (props: MemberOfHbacRulesProps) => {
   const someItemSelected = hbacRulesSelected.length > 0;
   const showTableRows = hbacRules.length > 0;
 
+  // Dialogs and actions
+  const [showAddModal, setShowAddModal] = React.useState(false);
+
   // Buttons functionality
   // - Refresh
   const isRefreshButtonEnabled =
     !fullHbacRulesQuery.isFetching && !props.isUserDataLoading;
+  const isAddButtonEnabled =
+    membershipDirection !== "indirect" && isRefreshButtonEnabled;
+
+  // Add new member to 'HBAC rules'
+  // API calls
+  const [addMemberToHbacRules] = useAddToHbacRulesMutation();
+  const [adderSearchValue, setAdderSearchValue] = React.useState("");
+  const [availableHbacRules, setAvailableHbacRules] = React.useState<
+    HBACRule[]
+  >([]);
+  const [availableItems, setAvailableItems] = React.useState<AvailableItems[]>(
+    []
+  );
+
+  // Load available HBAC rules, delay the search for opening the modal
+  const hbacRulesQuery = useGettingHbacRulesQuery({
+    search: adderSearchValue,
+    apiVersion: API_VERSION_BACKUP,
+    sizelimit: 100,
+    startIdx: 0,
+    stopIdx: 100,
+  });
+
+  // Trigger available HBAC rules search
+  React.useEffect(() => {
+    if (showAddModal) {
+      hbacRulesQuery.refetch();
+    }
+  }, [showAddModal, adderSearchValue, props.user]);
+
+  // Update available HBAC rules
+  React.useEffect(() => {
+    if (hbacRulesQuery.data && !hbacRulesQuery.isFetching) {
+      // transform data to HBAC rules
+      const count = hbacRulesQuery.data.result.count;
+      const results = hbacRulesQuery.data.result.results;
+      let items: AvailableItems[] = [];
+      const avalHbacRules: HBACRule[] = [];
+      for (let i = 0; i < count; i++) {
+        const hbacRule = apiToHBACRule(results[i].result);
+        avalHbacRules.push(hbacRule);
+        items.push({
+          key: hbacRule.cn,
+          title: hbacRule.cn,
+        });
+      }
+      items = items.filter((item) => !hbacRulesNamesToLoad.includes(item.key));
+
+      setAvailableHbacRules(avalHbacRules);
+      setAvailableItems(items);
+    }
+  }, [hbacRulesQuery.data, hbacRulesQuery.isFetching]);
+
+  // - Add
+  const onAddHbacRule = (items: AvailableItems[]) => {
+    const uid = props.user.uid;
+    const newHbacRuleNames = items.map((item) => item.key);
+    if (uid === undefined || newHbacRuleNames.length == 0) {
+      return;
+    }
+
+    addMemberToHbacRules([uid, "user", newHbacRuleNames]).then((response) => {
+      if ("data" in response) {
+        if (response.data.result) {
+          // Set alert: success
+          alerts.addAlert(
+            "add-member-success",
+            `Assigned new HBAC rule to user ${uid}`,
+            "success"
+          );
+          // Update displayed HBAC Rules before they are updated via refresh
+          const newHbacRules = hbacRules.concat(
+            availableHbacRules.filter((hbacRule) =>
+              newHbacRuleNames.includes(hbacRule.cn)
+            )
+          );
+          setHbacRules(newHbacRules);
+
+          // Refresh data
+          props.onRefreshUserData();
+          // Close modal
+          setShowAddModal(false);
+        } else if (response.data.error) {
+          // Set alert: error
+          const errorMessage = response.data.error as unknown as ErrorResult;
+          alerts.addAlert("add-member-error", errorMessage.message, "danger");
+        }
+      }
+    });
+  };
 
   return (
     <>
@@ -121,9 +221,8 @@ const MemberOfHbacRules = (props: MemberOfHbacRulesProps) => {
         deleteButtonEnabled={someItemSelected}
         // eslint-disable-next-line @typescript-eslint/no-empty-function
         onDeleteButtonClick={() => {}}
-        addButtonEnabled={true}
-        // eslint-disable-next-line @typescript-eslint/no-empty-function
-        onAddButtonClick={() => {}}
+        addButtonEnabled={isAddButtonEnabled}
+        onAddButtonClick={() => setShowAddModal(true)}
         membershipDirectionEnabled={true}
         membershipDirection={membershipDirection}
         onMembershipDirectionChange={setMembershipDirection}
@@ -150,6 +249,17 @@ const MemberOfHbacRules = (props: MemberOfHbacRulesProps) => {
         onSetPage={(_e, page) => setPage(page)}
         onPerPageSelect={(_e, perPage) => setPerPage(perPage)}
       />
+      {showAddModal && (
+        <MemberOfAddModal
+          showModal={showAddModal}
+          onCloseModal={() => setShowAddModal(false)}
+          availableItems={availableItems}
+          onAdd={onAddHbacRule}
+          onSearchTextChange={setAdderSearchValue}
+          title={`Assign HBAC rule to user ${props.user.uid}`}
+          ariaLabel="Add user of HBAC rule modal"
+        />
+      )}
     </>
   );
 };
diff --git a/src/services/rpc.ts b/src/services/rpc.ts
index fe32a36d..30f99ad3 100644
--- a/src/services/rpc.ts
+++ b/src/services/rpc.ts
@@ -170,7 +170,7 @@ export interface GenericPayload {
     | "group"
     | "netgroups"
     | "role"
-    | "hbacRule";
+    | "hbacrule";
 }
 
 export interface GroupShowPayload {
@@ -793,7 +793,7 @@ export const api = createApi({
           }
         }
 
-        if (objName === "hbacRule") {
+        if (objName === "hbacrule") {
           if (description) {
             params["description"] = description;
           }
@@ -836,7 +836,7 @@ export const api = createApi({
             id = idResponseData.result.result[i] as cnType;
           } else if (objName === "role") {
             id = idResponseData.result.result[i] as roleType;
-          } else if (objName === "hbacRule") {
+          } else if (objName === "hbacrule") {
             id = idResponseData.result.result[i] as cnType;
           } else {
             // Unknown, should never happen
@@ -1645,6 +1645,44 @@ export const api = createApi({
         return hbacRulesList;
       },
     }),
+    /**
+     * Add entity to HBAC rules
+     * @param {string} toId - ID of the entity to add to HBAC rules
+     * @param {string} type - Type of the entity
+     *    Available types: user | host | service | sourcehost
+     * @param {string[]} listOfMembers - List of members to add to the HBAC rules
+     */
+    addToHbacRules: build.mutation<
+      BatchRPCResponse,
+      [string, string, string[]]
+    >({
+      query: (payload) => {
+        const memberId = payload[0];
+        const memberType = payload[1];
+        const roleNames = payload[2];
+
+        let methodType = "";
+        if (memberType === "user") {
+          methodType = "hbacrule_add_user";
+        } else if (memberType === "host") {
+          methodType = "hbacrule_add_host";
+        } else if (memberType === "service") {
+          methodType = "hbacrule_add_service";
+        } else if (memberType === "sourcehost") {
+          methodType = "hbacrule_add_sourcehost";
+        }
+
+        const membersToAdd: Command[] = [];
+        roleNames.map((roleName) => {
+          const payloadItem = {
+            method: methodType,
+            params: [[roleName], { [memberType]: memberId }],
+          } as Command;
+          membersToAdd.push(payloadItem);
+        });
+        return getBatchCommand(membersToAdd, API_VERSION_BACKUP);
+      },
+    }),
   }),
 });
 
@@ -1708,8 +1746,9 @@ export const useGettingRolesQuery = (payloadData, options) => {
   payloadData["objAttr"] = "cn";
   return useGettingGenericQuery(payloadData, options);
 };
+// HBAC rules
 export const useGettingHbacRulesQuery = (payloadData) => {
-  payloadData["objName"] = "hbacRule";
+  payloadData["objName"] = "hbacrule";
   payloadData["objAttr"] = "cn";
   return useGettingGenericQuery(payloadData);
 };
@@ -1796,4 +1835,5 @@ export const {
   useRemoveFromRolesMutation,
   useGetRolesInfoByNameQuery,
   useGetHbacRulesInfoByNameQuery,
+  useAddToHbacRulesMutation,
 } = api;