diff --git a/app/Http/Requests/ContractRequest.php b/app/Http/Requests/ContractRequest.php
index 4af543f..4c5bccc 100644
--- a/app/Http/Requests/ContractRequest.php
+++ b/app/Http/Requests/ContractRequest.php
@@ -2,6 +2,7 @@
 
 namespace App\Http\Requests;
 
+use App\Models\Contract;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Validator;
 use Carbon\Carbon;
@@ -96,6 +97,31 @@ class ContractRequest extends FormRequest
     public function withValidator(Validator $validator)
     {
         $validator->after(function ($validator) {
+            if ($this->filled('code') && $this->filled('supply_type')) {
+                $contractId = $this->route('id');
+                $existingContract = Contract::query()
+                    ->with('client:id,name')
+                    ->where('code', $this->input('code'))
+                    ->where('supply_type', $this->input('supply_type'))
+                    ->when($contractId, fn ($query) => $query->where('id', '!=', $contractId))
+                    ->first();
+
+                if ($existingContract && ! $this->boolean('confirm_duplicate')) {
+                    $supplyType = strtoupper($this->input('supply_type'));
+                    $clientName = $existingContract->client?->name;
+                    $message = "Já existe um contrato {$supplyType} com este código";
+
+                    if ($clientName) {
+                        $message .= " associado ao cliente {$clientName}";
+                    }
+
+                    $validator->errors()->add(
+                        'duplicate_code',
+                        $message . '. Confirme apenas se se trata de uma mudança de titularidade.'
+                    );
+                }
+            }
+
             if (! $this->user()?->can('view_contract_summary')) {
                 return;
             }
diff --git a/resources/views/web/contract/add_edit.blade.php b/resources/views/web/contract/add_edit.blade.php
index 4542681..78afa90 100644
--- a/resources/views/web/contract/add_edit.blade.php
+++ b/resources/views/web/contract/add_edit.blade.php
@@ -635,5 +635,39 @@
             applyColor('previous_supplier_select');
         });
     });
+
+    const duplicateCodeMessage = @json($errors->first('duplicate_code'));
+    if (duplicateCodeMessage) {
+        const form = document.querySelector('form');
+        const submitConfirmed = () => {
+            let confirmation = form.querySelector('input[name="confirm_duplicate"]');
+            if (!confirmation) {
+                confirmation = document.createElement('input');
+                confirmation.type = 'hidden';
+                confirmation.name = 'confirm_duplicate';
+                form.appendChild(confirmation);
+            }
+            confirmation.value = '1';
+            form.submit();
+        };
+
+        if (window.Swal) {
+            Swal.fire({
+                title: 'CPE/CUI já existente',
+                text: duplicateCodeMessage,
+                icon: 'warning',
+                showCancelButton: true,
+                confirmButtonText: 'Aceitar e gravar',
+                cancelButtonText: 'Cancelar',
+                reverseButtons: true
+            }).then((result) => {
+                if (result.isConfirmed) {
+                    submitConfirmed();
+                }
+            });
+        } else if (window.confirm(`${duplicateCodeMessage}\n\nDeseja continuar?`)) {
+            submitConfirmed();
+        }
+    }
 </script>
 @endsection
diff --git a/tests/Feature/ContractPersistenceTest.php b/tests/Feature/ContractPersistenceTest.php
index eeb7d27..b4380bd 100644
--- a/tests/Feature/ContractPersistenceTest.php
+++ b/tests/Feature/ContractPersistenceTest.php
@@ -7,6 +7,7 @@ use App\Models\Contract;
 use App\Services\ContractService;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
+use Illuminate\Support\Facades\Validator;
 use Illuminate\Validation\ValidationException;
 use Tests\Support\IsolatedDatabaseTestCase;
 
@@ -15,7 +16,38 @@ class ContractPersistenceTest extends IsolatedDatabaseTestCase
     protected function setUp(): void
     {
         parent::setUp();
-        Schema::table('contracts', fn (Blueprint $table) => $table->decimal('go_ki')->nullable());
+        Schema::table('contracts', function (Blueprint $table) {
+            $table->decimal('go_ki')->nullable();
+            $table->string('code')->nullable();
+            $table->string('supply_type')->nullable();
+        });
+    }
+
+    public function test_duplicate_supply_code_requires_explicit_confirmation(): void
+    {
+        $user = $this->authenticate();
+        Contract::create([
+            'client_id' => 1,
+            'code' => 'CPE-123',
+            'supply_type' => 'cpe',
+        ]);
+
+        $request = ContractRequest::create('/contract', 'POST', [
+            'code' => 'CPE-123',
+            'supply_type' => 'cpe',
+        ]);
+        $request->setUserResolver(fn () => $user);
+        $validator = Validator::make($request->all(), []);
+        $request->withValidator($validator);
+
+        $this->assertFalse($validator->passes());
+        $this->assertArrayHasKey('duplicate_code', $validator->errors()->messages());
+
+        $request->merge(['confirm_duplicate' => '1']);
+        $confirmedValidator = Validator::make($request->all(), []);
+        $request->withValidator($confirmedValidator);
+
+        $this->assertTrue($confirmedValidator->passes());
     }
 
     public function test_update_persists_chargeback_and_deducts_it_from_profit(): void