diff --git a/app/Cart/CartCollection.php b/app/Cart/CartCollection.php
index 304367f..15f783a 100644
--- a/app/Cart/CartCollection.php
+++ b/app/Cart/CartCollection.php
@@ -111,7 +111,15 @@ class CartCollection
             $item->subtotal = $item->product->getPrice('credit') * $item->qty;
         }
 
-        $content[$draftKey]->addItem($item);
+        $foundItem = $draft->search($item->product);
+
+        if (!is_null($foundItem)) {
+            $itemKey = $draft->searchItemKeyFor($item->product);
+            $content[$draftKey]->updateItem($itemKey, ['qty' => $foundItem->qty + $item->qty]);
+        } else {
+            $content[$draftKey]->addItem($item);
+        }
+
 
         $this->session->put($this->instance, $content);
 
diff --git a/app/Cart/TransactionDraft.php b/app/Cart/TransactionDraft.php
index e2be1a5..5b07a19 100644
--- a/app/Cart/TransactionDraft.php
+++ b/app/Cart/TransactionDraft.php
@@ -98,6 +98,13 @@ abstract class TransactionDraft
         return $productItem;
     }
 
+    public function searchItemKeyFor(Product $product)
+    {
+        return $this->items()->search(function($item, $key) use ($product) {
+            return $item->product->id == $product->id;
+        });
+    }
+
     public function getExchange()
     {
         return $this->payment - $this->getTotal();
diff --git a/app/Product.php b/app/Product.php
index 076e9c7..22f716c 100644
--- a/app/Product.php
+++ b/app/Product.php
@@ -6,7 +6,7 @@ use Illuminate\Database\Eloquent\Model;
 
 class Product extends Model
 {
-    protected $fillable = ['name', 'cash_price', 'credit_price', 'unit_id'];
+    protected $fillable = ['id', 'name', 'cash_price', 'credit_price', 'unit_id'];
 
     public function getPrice($type = 'cash')
     {
diff --git a/tests/Unit/CartCollectionTest.php b/tests/Unit/CartCollectionTest.php
index 2d596c4..18356ea 100644
--- a/tests/Unit/CartCollectionTest.php
+++ b/tests/Unit/CartCollectionTest.php
@@ -159,6 +159,30 @@ class CartCollectionTest extends TestCase
 
         $cart->addItemToDraft($draft->draftKey, $item);
         $this->assertEquals(2000, $draft->getTotal());
+        $this->assertEquals(1, $draft->getItemsCount());
+        $this->assertEquals(2, $draft->getTotalQty());
+    }
+
+    /** @test */
+    public function it_adds_product_qty_to_draft_if_product_id_exists()
+    {
+        $cart = new CartCollection();
+
+        $draft = $cart->add(new CashDraft());
+        $count = 2;
+
+        $item = new Item(new Product(['id' => 1, 'cash_price' => 1000]), $count);
+        $cart->addItemToDraft($draft->draftKey, $item);
+
+        $item = new Item(new Product(['id' => 1, 'cash_price' => 1000]), $count);
+        $cart->addItemToDraft($draft->draftKey, $item);
+
+        $item = new Item(new Product(['id' => 2, 'cash_price' => 1000]), $count);
+        $cart->addItemToDraft($draft->draftKey, $item);
+
+        $this->assertEquals(6000, $draft->getTotal());
+        $this->assertEquals(2, $draft->getItemsCount());
+        $this->assertEquals(6, $draft->getTotalQty());
     }
 
     /** @test */
diff --git a/tests/Unit/Integration/TransactionDraftTest.php b/tests/Unit/Integration/TransactionDraftTest.php
index 158a411..5eb9f47 100644
--- a/tests/Unit/Integration/TransactionDraftTest.php
+++ b/tests/Unit/Integration/TransactionDraftTest.php
@@ -158,8 +158,8 @@ class TransactionDraftTest extends TestCase
 
         $draft = $cart->add(new CashDraft());
 
-        $product1 = factory(Product::class)->make(['cash_price' => 1000]);
-        $product2 = factory(Product::class)->make(['cash_price' => 2000]);
+        $product1 = factory(Product::class)->create(['cash_price' => 1000]);
+        $product2 = factory(Product::class)->create(['cash_price' => 2000]);
         $item1 = new Item($product1, 1);
         $item2 = new Item($product2, 3);
         // Add items to draft
@@ -223,4 +223,45 @@ class TransactionDraftTest extends TestCase
             'user_id'    => 1,
         ]);
     }
+
+    /** @test */
+    public function it_has_product_search_method()
+    {
+        $cart = new CartCollection();
+
+        $draft = $cart->add(new CashDraft());
+        $count = 2;
+        $product1 = factory(Product::class)->create(['cash_price' => 1000]);
+        $item1 = new Item($product1, $count);
+
+        // Add items to draft
+        $cart->addItemToDraft($draft->draftKey, $item1);
+
+        $this->assertEquals($draft->search($product1)->id, $product1->id);
+    }
+
+    /** @test */
+    public function it_has_search_item_key_for_product_method()
+    {
+        $cart = new CartCollection();
+
+        $draft = $cart->add(new CashDraft());
+        $count = 2;
+
+        $product1 = factory(Product::class)->create();
+        $item1 = new Item($product1, $count);
+        $cart->addItemToDraft($draft->draftKey, $item1);
+
+        $product2 = factory(Product::class)->create();
+        $item2 = new Item($product2, $count);
+        $cart->addItemToDraft($draft->draftKey, $item2);
+
+        $product3 = factory(Product::class)->create();
+        $item3 = new Item($product3, $count);
+        $cart->addItemToDraft($draft->draftKey, $item3);
+
+        $this->assertEquals($draft->searchItemKeyFor($product3), 2);
+        $this->assertEquals($draft->searchItemKeyFor($product2), 1);
+        $this->assertEquals($draft->searchItemKeyFor($product1), 0);
+    }
 }