diff --git a/extension.neon b/extension.neon
index b9d3e7b..86801f5 100644
--- a/extension.neon
+++ b/extension.neon
@@ -3,6 +3,10 @@ services:
 		class: Nextras\OrmPhpStan\Types\CollectionReturnTypeExtension
 		tags:
 			- phpstan.broker.dynamicMethodReturnTypeExtension
+	-
+		class: Nextras\OrmPhpStan\Types\MapperMethodReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicMethodReturnTypeExtension
 	-
 		class: Nextras\OrmPhpStan\Types\RelationshipReturnTypeExtension
 		tags:
diff --git a/src/Types/MapperMethodReturnTypeExtension.php b/src/Types/MapperMethodReturnTypeExtension.php
new file mode 100644
index 0000000..99eb4df
--- /dev/null
+++ b/src/Types/MapperMethodReturnTypeExtension.php
@@ -0,0 +1,94 @@
+<?php declare(strict_types = 1);
+
+namespace Nextras\OrmPhpStan\Types;
+
+use Nextras\Orm\Collection\ICollection;
+use Nextras\Orm\Mapper\Dbal\DbalMapper;
+use Nextras\OrmPhpStan\Types\Helpers\RepositoryEntityTypeHelper;
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\ShouldNotHappenException;
+use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\IntegerType;
+use PHPStan\Type\IterableType;
+use PHPStan\Type\ObjectType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeWithClassName;
+
+
+class MapperMethodReturnTypeExtension implements DynamicMethodReturnTypeExtension
+{
+	/** @var RepositoryEntityTypeHelper */
+	private $repositoryEntityTypeHelper;
+
+
+	public function __construct(RepositoryEntityTypeHelper $repositoryEntityTypeHelper)
+	{
+		$this->repositoryEntityTypeHelper = $repositoryEntityTypeHelper;
+	}
+
+
+	public function getClass(): string
+	{
+		return DbalMapper::class;
+	}
+
+
+	public function isMethodSupported(MethodReflection $methodReflection): bool
+	{
+		static $methods = [
+			'toEntity',
+			'toCollection',
+		];
+		return in_array($methodReflection->getName(), $methods, true);
+	}
+
+
+	public function getTypeFromMethodCall(
+		MethodReflection $methodReflection,
+		MethodCall $methodCall,
+		Scope $scope
+	): Type
+	{
+		$mapper = $scope->getType($methodCall->var);
+		\assert($mapper instanceof TypeWithClassName);
+
+		$defaultReturn = ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+
+		if ($mapper->getClassName() === DbalMapper::class) {
+			return $defaultReturn;
+		}
+
+		$mapperClass = $mapper->getClassName();
+		do {
+			$repositoryClass = \str_replace('Mapper', 'Repository', $mapperClass);
+			$mapperClass = \get_parent_class($mapperClass);
+		} while (!\class_exists($repositoryClass) && $mapperClass !== DbalMapper::class);
+
+		try {
+			$repository = new \ReflectionClass($repositoryClass);
+		} catch (\ReflectionException $e) {
+			return $defaultReturn;
+		}
+
+		$entityType = $this->repositoryEntityTypeHelper->resolveFirst(
+			$repository,
+			$scope
+		);
+
+		$methodName = $methodReflection->getName();
+		if ($methodName === 'toEntity') {
+			return TypeCombinator::addNull($entityType);
+		} elseif ($methodName === 'toCollection') {
+			return TypeCombinator::intersect(
+				new ObjectType(ICollection::class),
+				new IterableType(new IntegerType(), $entityType)
+			);
+		}
+
+		throw new ShouldNotHappenException();
+	}
+}
diff --git a/tests/testbox/Types/MapperTest.php b/tests/testbox/Types/MapperTest.php
new file mode 100644
index 0000000..bf2223b
--- /dev/null
+++ b/tests/testbox/Types/MapperTest.php
@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace NextrasTests\OrmPhpStan\Types;
+
+
+class MapperTest extends AuthorsMapper
+{
+	public function testOk()
+	{
+		$this->takeAuthors($this->toCollection([]));
+		$this->takeAuthor($this->toEntity([]));
+	}
+
+
+	private function takeAuthor(?Author $author)
+	{
+	}
+
+
+	/**
+	 * @param iterable<int, Author> $authors
+	 */
+	private function takeAuthors($authors)
+	{
+	}
+}
diff --git a/tests/testbox/Types/fixtures/AuthorsMapper.php b/tests/testbox/Types/fixtures/AuthorsMapper.php
new file mode 100644
index 0000000..54d1748
--- /dev/null
+++ b/tests/testbox/Types/fixtures/AuthorsMapper.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types = 1);
+
+namespace NextrasTests\OrmPhpStan\Types;
+
+use Nextras\Orm\Mapper\Mapper;
+
+
+class AuthorsMapper extends Mapper
+{
+}