diff --git a/docs/IMPLEMENTATION_PLAN.md b/docs/IMPLEMENTATION_PLAN.md
index f338c16..257e392 100644
--- a/docs/IMPLEMENTATION_PLAN.md
+++ b/docs/IMPLEMENTATION_PLAN.md
@@ -1719,7 +1719,7 @@ public enum CashBookEntryType { Income = 0, Expense = 1 }
 | ✓ | K18 | Web | Export Controller | 1 |
 | ✓ | K19 | Web | Membership Fees Feature | 2 |
 | ✓ | K20 | Web | Club Settings Extension | 3 |
-| ☐ | K21 | Web | Navigation Integration | 1 |
+| ✓ | K21 | Web | Navigation Integration | 1 |
 | ☐ | K22 | Tests | Unit Tests | 2 |
 | ☐ | K23 | Tests | Integration Tests | 1 |
 
diff --git a/src/Koogle.Web/Components/Layout/NavMenu.razor b/src/Koogle.Web/Components/Layout/NavMenu.razor
index ac6dd54..24a1814 100644
--- a/src/Koogle.Web/Components/Layout/NavMenu.razor
+++ b/src/Koogle.Web/Components/Layout/NavMenu.razor
@@ -22,7 +22,30 @@
             Spieltage
         </MudNavLink>
 
+        @if (AuthState.Value.IsClubTreasurer || AuthState.Value.IsClubAdmin || AuthState.Value.IsSuperAdmin)
+        {
+            <MudNavGroup Title="Kassenbuch"
+                         Icon="@Icons.Material.Filled.AccountBalance"
+                         Expanded="false">
+                <MudNavLink Href="/cashbook"
+                            Match="NavLinkMatch.All"
+                            Icon="@Icons.Material.Filled.Book">
+                    &Uuml;bersicht
+                </MudNavLink>
 
+                <MudNavLink Href="/cashbook/categories"
+                            Match="NavLinkMatch.Prefix"
+                            Icon="@Icons.Material.Filled.Category">
+                    Kategorien
+                </MudNavLink>
+
+                <MudNavLink Href="/cashbook/reports"
+                            Match="NavLinkMatch.Prefix"
+                            Icon="@Icons.Material.Filled.Assessment">
+                    Berichte
+                </MudNavLink>
+            </MudNavGroup>
+        }
 
         @if (AuthState.Value.IsClubAdmin || AuthState.Value.IsSuperAdmin)
         {
diff --git a/src/Koogle.Web/Store/AuthState/AuthState.cs b/src/Koogle.Web/Store/AuthState/AuthState.cs
index d393088..0e393e1 100644
--- a/src/Koogle.Web/Store/AuthState/AuthState.cs
+++ b/src/Koogle.Web/Store/AuthState/AuthState.cs
@@ -62,6 +62,11 @@ public record AuthState
     /// </summary>
     public bool IsClubAdmin { get; set; }
 
+    /// <summary>
+    /// Whether the user is a Club Treasurer (Kassenwart).
+    /// </summary>
+    public bool IsClubTreasurer { get; set; }
+
     /// <summary>
     /// Whether the user is a Club Editor.
     /// </summary>
@@ -92,6 +97,7 @@ public record AuthState
         AvailableClubs = [],
         IsSuperAdmin = false,
         IsClubAdmin = false,
+        IsClubTreasurer = false,
         IsClubEditor = false,
         IsClubViewer = false,
         Roles = [],
@@ -107,12 +113,14 @@ public record AuthState
     {
         var isSuperAdmin = roles.Contains(UserRole.SuperAdmin);
         var isClubAdmin = roles.Contains(UserRole.Admin);
+        var isClubTreasurer = roles.Contains(UserRole.Treasurer);
         var isClubEditor = roles.Contains(UserRole.Editor);
         var isClubViewer = roles.Contains(UserRole.Viewer);
 
         var highestRole = string.Empty;
         if (isSuperAdmin) highestRole = UserRole.SuperAdmin;
         else if (isClubAdmin) highestRole = UserRole.Admin;
+        else if (isClubTreasurer) highestRole = UserRole.Treasurer;
         else if (isClubEditor) highestRole = UserRole.Editor;
         else highestRole = UserRole.Viewer;
 
@@ -121,6 +129,7 @@ public record AuthState
             Roles = roles,
             IsSuperAdmin = isSuperAdmin,
             IsClubAdmin = isClubAdmin,
+            IsClubTreasurer = isClubTreasurer,
             IsClubEditor = isClubEditor,
             IsClubViewer = isClubViewer,
             HighestRole = highestRole