diff --git a/src/CacheItem.php b/src/CacheItem.php
index d1b6abd..75a6fce 100644
--- a/src/CacheItem.php
+++ b/src/CacheItem.php
@@ -3,13 +3,12 @@
 namespace yii1tech\psr\cache;
 
 use CComponent;
-use Psr\Cache\CacheItemInterface;
 
 /**
  * @author Paul Klimov <klimov.paul@gmail.com>
  * @since 1.0
  */
-class CacheItem extends CComponent implements CacheItemInterface
+class CacheItem extends CComponent implements CacheItemContract
 {
     /**
      * @var string cache item key (ID).
@@ -26,6 +25,11 @@ class CacheItem extends CComponent implements CacheItemInterface
      */
     private $_expire;
 
+    /**
+     * @var \ICacheDependency|null dependency of the cache item.
+     */
+    private $_dependency;
+
     /**
      * Sets the key for the current cache item.
      *
@@ -47,6 +51,25 @@ public function getExpire()
         return $this->_expire;
     }
 
+    /**
+     * @return \ICacheDependency|null dependency of the cache item.
+     */
+    public function getDependency(): ?\ICacheDependency
+    {
+        return $this->_dependency;
+    }
+
+    /**
+     * @param \ICacheDependency|null $dependency dependency of the cache item.
+     * @return static self reference.
+     */
+    public function setDependency(?\ICacheDependency $dependency): self
+    {
+        $this->_dependency = $dependency;
+
+        return $this;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -115,4 +138,12 @@ public function expiresAfter($time): self
 
         return $this;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function depends(?\ICacheDependency $dependency): self
+    {
+        return $this->setDependency($dependency);
+    }
 }
\ No newline at end of file
diff --git a/src/CacheItemContract.php b/src/CacheItemContract.php
new file mode 100644
index 0000000..76bb956
--- /dev/null
+++ b/src/CacheItemContract.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace yii1tech\psr\cache;
+
+use Psr\Cache\CacheItemInterface;
+
+/**
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 1.0
+ */
+interface CacheItemContract extends CacheItemInterface
+{
+    /**
+     * Sets dependency of the cached item. If the dependency changes, the item is labelled invalid.
+     *
+     * @param \ICacheDependency|null $dependency dependency of the cached item.
+     * @return static self reference.
+     */
+    public function depends(?\ICacheDependency $dependency);
+}
\ No newline at end of file
diff --git a/src/CacheItemPool.php b/src/CacheItemPool.php
index a6096b4..d98e72d 100644
--- a/src/CacheItemPool.php
+++ b/src/CacheItemPool.php
@@ -175,8 +175,8 @@ public function save(CacheItemInterface $item): bool
         return $this->getCache()->set(
             $item->getKey(),
             $item->get(),
-            $item->getExpire()
-            // @todo dependency
+            $item->getExpire(),
+            $item->getDependency()
         );
     }
 
diff --git a/tests/CacheItemPoolTest.php b/tests/CacheItemPoolTest.php
index 2abbdf4..ec6d574 100644
--- a/tests/CacheItemPoolTest.php
+++ b/tests/CacheItemPoolTest.php
@@ -200,4 +200,36 @@ public function testAutoCommit(): void
 
         $this->assertSame($value, $cache->get($key));
     }
+
+    /**
+     * @depends testSave
+     */
+    public function testSaveWithDependency(): void
+    {
+        $pool = new CacheItemPool();
+
+        $GLOBALS['test_state'] = 1;
+
+        $key = 'test';
+        $value = 'test-value';
+
+        $item = $pool->getItem($key);
+        $item->set($value);
+        $item->expiresAfter(DateInterval::createFromDateString('1 hour'));
+        $item->depends(new \CExpressionDependency('$GLOBALS["test_state"] == 1'));
+
+        $this->assertTrue($pool->save($item));
+
+        $this->assertTrue($pool->hasItem($key));
+
+        $item = $pool->getItem($key);
+        $this->assertTrue($item->isHit());
+
+        $GLOBALS['test_state'] = 2;
+
+        $this->assertFalse($pool->hasItem($key));
+
+        $item = $pool->getItem($key);
+        $this->assertFalse($item->isHit());
+    }
 }
\ No newline at end of file