diff --git a/src/routes/api/auth/callback/github.ts b/src/routes/api/auth/callback/github.ts
index c306e57..b59f43e 100644
--- a/src/routes/api/auth/callback/github.ts
+++ b/src/routes/api/auth/callback/github.ts
@@ -11,7 +11,7 @@ export async function GET(event: APIEvent) {
   if (error) {
     return new Response(null, {
       status: 302,
-      headers: { Location: `/login?error=${encodeURIComponent(error)}` },
+      headers: { Location: `/login?error=${encodeURIComponent(error)}` }
     });
   }
 
@@ -19,7 +19,7 @@ export async function GET(event: APIEvent) {
   if (!code) {
     return new Response(null, {
       status: 302,
-      headers: { Location: "/login?error=missing_code" },
+      headers: { Location: "/login?error=missing_code" }
     });
   }
 
@@ -35,20 +35,33 @@ export async function GET(event: APIEvent) {
       // Redirect to account page on success
       return new Response(null, {
         status: 302,
-        headers: { Location: result.redirectTo || "/account" },
+        headers: { Location: result.redirectTo || "/account" }
       });
     } else {
       // Redirect to login with error
       return new Response(null, {
         status: 302,
-        headers: { Location: "/login?error=auth_failed" },
+        headers: { Location: "/login?error=auth_failed" }
       });
     }
   } catch (error) {
     console.error("GitHub OAuth callback error:", error);
+
+    // Handle specific TRPC errors
+    if (error && typeof error === "object" && "code" in error) {
+      const trpcError = error as { code: string; message?: string };
+
+      if (trpcError.code === "CONFLICT") {
+        return new Response(null, {
+          status: 302,
+          headers: { Location: "/login?error=email_in_use" }
+        });
+      }
+    }
+
     return new Response(null, {
       status: 302,
-      headers: { Location: "/login?error=server_error" },
+      headers: { Location: "/login?error=server_error" }
     });
   }
 }
diff --git a/src/routes/api/auth/callback/google.ts b/src/routes/api/auth/callback/google.ts
index d99e4c2..d044650 100644
--- a/src/routes/api/auth/callback/google.ts
+++ b/src/routes/api/auth/callback/google.ts
@@ -11,7 +11,7 @@ export async function GET(event: APIEvent) {
   if (error) {
     return new Response(null, {
       status: 302,
-      headers: { Location: `/login?error=${encodeURIComponent(error)}` },
+      headers: { Location: `/login?error=${encodeURIComponent(error)}` }
     });
   }
 
@@ -19,7 +19,7 @@ export async function GET(event: APIEvent) {
   if (!code) {
     return new Response(null, {
       status: 302,
-      headers: { Location: "/login?error=missing_code" },
+      headers: { Location: "/login?error=missing_code" }
     });
   }
 
@@ -35,20 +35,33 @@ export async function GET(event: APIEvent) {
       // Redirect to account page on success
       return new Response(null, {
         status: 302,
-        headers: { Location: result.redirectTo || "/account" },
+        headers: { Location: result.redirectTo || "/account" }
       });
     } else {
       // Redirect to login with error
       return new Response(null, {
         status: 302,
-        headers: { Location: "/login?error=auth_failed" },
+        headers: { Location: "/login?error=auth_failed" }
       });
     }
   } catch (error) {
     console.error("Google OAuth callback error:", error);
+
+    // Handle specific TRPC errors
+    if (error && typeof error === "object" && "code" in error) {
+      const trpcError = error as { code: string; message?: string };
+
+      if (trpcError.code === "CONFLICT") {
+        return new Response(null, {
+          status: 302,
+          headers: { Location: "/login?error=email_in_use" }
+        });
+      }
+    }
+
     return new Response(null, {
       status: 302,
-      headers: { Location: "/login?error=server_error" },
+      headers: { Location: "/login?error=server_error" }
     });
   }
 }
diff --git a/src/routes/login/index.tsx b/src/routes/login/index.tsx
index e99fb68..952546c 100644
--- a/src/routes/login/index.tsx
+++ b/src/routes/login/index.tsx
@@ -111,7 +111,9 @@ export default function LoginPage() {
         server_error: "Server error - please try again later",
         missing_params: "Invalid login link - missing parameters",
         link_expired: "Login link has expired - please request a new one",
-        access_denied: "Access denied - you cancelled the login"
+        access_denied: "Access denied - you cancelled the login",
+        email_in_use:
+          "This email is already associated with another account. Please sign in with that account instead."
       };
       setError(errorMessages[errorParam] || "An error occurred during login");
     }
@@ -333,11 +335,22 @@ export default function LoginPage() {
         {/* Main content */}
         <div class="pt-12 md:pt-24">
           {/* Error message */}
-          <div class="absolute -mt-12 text-center text-3xl text-red-400 italic">
+          <div class="absolute -mt-12 text-center text-red-400 italic">
             <Show when={error() === "passwordMismatch"}>
-              Passwords did not match!
+              <div class="text-3xl">Passwords did not match!</div>
+            </Show>
+            <Show when={error() === "duplicate"}>
+              <div class="text-3xl">Email Already Exists!</div>
+            </Show>
+            <Show
+              when={
+                error() &&
+                error() !== "passwordMismatch" &&
+                error() !== "duplicate"
+              }
+            >
+              <div class="max-w-md px-4 text-base">{error()}</div>
             </Show>
-            <Show when={error() === "duplicate"}>Email Already Exists!</Show>
           </div>
 
           {/* Title */}
diff --git a/src/server/api/routers/auth.ts b/src/server/api/routers/auth.ts
index e1efd01..5546b97 100644
--- a/src/server/api/routers/auth.ts
+++ b/src/server/api/routers/auth.ts
@@ -154,10 +154,25 @@ export const authRouter = createTRPCRouter({
           // User exists - update email and image if changed
           userId = (res.rows[0] as unknown as User).id;
 
-          await conn.execute({
-            sql: `UPDATE User SET email = ?, email_verified = ?, image = ? WHERE id = ?`,
-            args: [email, emailVerified ? 1 : 0, icon, userId]
-          });
+          try {
+            await conn.execute({
+              sql: `UPDATE User SET email = ?, email_verified = ?, image = ? WHERE id = ?`,
+              args: [email, emailVerified ? 1 : 0, icon, userId]
+            });
+          } catch (updateError: any) {
+            // Handle unique constraint error on email
+            if (
+              updateError.code === "SQLITE_CONSTRAINT" &&
+              updateError.message?.includes("User.email")
+            ) {
+              throw new TRPCError({
+                code: "CONFLICT",
+                message:
+                  "This email is already associated with another account. Please sign in with that account or use a different email address."
+              });
+            }
+            throw updateError;
+          }
         } else {
           // Create new user
           userId = uuidV4();
@@ -171,7 +186,23 @@ export const authRouter = createTRPCRouter({
             "github",
             icon
           ];
-          await conn.execute({ sql: insertQuery, args: insertParams });
+
+          try {
+            await conn.execute({ sql: insertQuery, args: insertParams });
+          } catch (insertError: any) {
+            // Handle unique constraint error on email
+            if (
+              insertError.code === "SQLITE_CONSTRAINT" &&
+              insertError.message?.includes("User.email")
+            ) {
+              throw new TRPCError({
+                code: "CONFLICT",
+                message:
+                  "This email is already associated with another account. Please sign in with that account or use a different email address."
+              });
+            }
+            throw insertError;
+          }
         }
 
         // Create JWT token
@@ -291,6 +322,7 @@ export const authRouter = createTRPCRouter({
           // User exists - update email, email_verified, display_name, and image if changed
           userId = (res.rows[0] as unknown as User).id;
 
+          // No need to catch constraint error here since we're updating the same user's record
           await conn.execute({
             sql: `UPDATE User SET email = ?, email_verified = ?, display_name = ?, image = ? WHERE id = ?`,
             args: [email, email_verified ? 1 : 0, name, image, userId]
@@ -308,10 +340,26 @@ export const authRouter = createTRPCRouter({
             "google",
             image
           ];
-          await conn.execute({
-            sql: insertQuery,
-            args: insertParams
-          });
+
+          try {
+            await conn.execute({
+              sql: insertQuery,
+              args: insertParams
+            });
+          } catch (insertError: any) {
+            // Handle unique constraint error on email
+            if (
+              insertError.code === "SQLITE_CONSTRAINT" &&
+              insertError.message?.includes("User.email")
+            ) {
+              throw new TRPCError({
+                code: "CONFLICT",
+                message:
+                  "This email is already associated with another account. Please sign in with that account instead."
+              });
+            }
+            throw insertError;
+          }
         }
 
         // Create JWT token