diff --git a/fastcrud/crud/fast_crud.py b/fastcrud/crud/fast_crud.py
index 0f4f8a7..d4060c5 100644
--- a/fastcrud/crud/fast_crud.py
+++ b/fastcrud/crud/fast_crud.py
@@ -1,4 +1,4 @@
-from typing import Any, Generic, TypeVar, Union, Optional
+from typing import Any, Dict, Generic, TypeVar, Union, Optional
 from datetime import datetime, timezone
 
 from pydantic import BaseModel, ValidationError
@@ -190,6 +190,7 @@ def __init__(
         self.is_deleted_column = is_deleted_column
         self.deleted_at_column = deleted_at_column
         self.updated_at_column = updated_at_column
+        self._primary_keys = _get_primary_keys(self.model)
 
     def _parse_filters(
         self, model: Optional[Union[type[ModelType], AliasedClass]] = None, **kwargs
@@ -453,6 +454,7 @@ async def get(
         Args:
             db: The database session to use for the operation.
             schema_to_select: Optional Pydantic schema for selecting specific columns.
+            return_as_model: If True, converts the fetched data to Pydantic models based on schema_to_select. Defaults to False.
             one_or_none: Flag to get strictly one or no result. Multiple results are not allowed.
             **kwargs: Filters to apply to the query, using field names for direct matches or appending comparison operators for advanced queries.
 
@@ -498,6 +500,52 @@ async def get(
             )
         return schema_to_select(**out)
 
+    def _get_pk_dict(self, instance):
+        return {pk.name: getattr(instance, pk.name) for pk in self._primary_keys}
+
+    async def upsert(
+        self,
+        db: AsyncSession,
+        instance: Union[UpdateSchemaType, CreateSchemaType],
+        schema_to_select: Optional[type[BaseModel]] = None,
+        return_as_model: bool = False,
+    ) -> Union[BaseModel, Dict[str, Any], None]:
+        """Update the instance or create it if it doesn't exists.
+        Note: This method will perform two transactions to the database (get and create or update).
+
+        Args:
+            db (AsyncSession): The database session to use for the operation.
+            instance (Union[UpdateSchemaType, type[BaseModel]]): A Pydantic schema representing the instance.
+            schema_to_select (Optional[type[BaseModel]], optional): Optional Pydantic schema for selecting specific columns. Defaults to None.
+            return_as_model (bool, optional): If True, converts the fetched data to Pydantic models based on schema_to_select. Defaults to False.
+
+        Returns:
+            BaseModel: the created or updated instance
+        """
+        _pks = self._get_pk_dict(instance)
+        schema_to_select = schema_to_select or type(instance)
+        db_instance = await self.get(
+            db,
+            schema_to_select=schema_to_select,
+            return_as_model=return_as_model,
+            **_pks,
+        )
+        if db_instance is None:
+            db_instance = await self.create(db, instance)  # type: ignore
+            db_instance = schema_to_select.model_validate(
+                db_instance, from_attributes=True
+            )
+        else:
+            await self.update(db, instance)  # type: ignore
+            db_instance = await self.get(
+                db,
+                schema_to_select=schema_to_select,
+                return_as_model=return_as_model,
+                **_pks,
+            )
+
+        return db_instance
+
     async def exists(self, db: AsyncSession, **kwargs: Any) -> bool:
         """
         Checks if any records exist that match the given filter conditions.
diff --git a/tests/sqlalchemy/conftest.py b/tests/sqlalchemy/conftest.py
index e52fc45..18b325b 100644
--- a/tests/sqlalchemy/conftest.py
+++ b/tests/sqlalchemy/conftest.py
@@ -370,7 +370,7 @@ def client(
 
 
 @pytest.fixture
-def endpoint_creator() -> EndpointCreator:
+def endpoint_creator(test_model) -> EndpointCreator:
     """Fixture to create an instance of EndpointCreator."""
     return EndpointCreator(
         session=get_session_local,
diff --git a/tests/sqlalchemy/crud/test_upsert.py b/tests/sqlalchemy/crud/test_upsert.py
new file mode 100644
index 0000000..7fdaba2
--- /dev/null
+++ b/tests/sqlalchemy/crud/test_upsert.py
@@ -0,0 +1,16 @@
+import pytest
+
+from fastcrud.crud.fast_crud import FastCRUD
+
+
+@pytest.mark.asyncio
+async def test_upsert_successful(async_session, test_model, read_schema):
+    crud = FastCRUD(test_model)
+    new_data = read_schema(id=1, name="New Record", tier_id=1, category_id=1)
+    fetched_record = await crud.upsert(async_session, new_data, return_as_model=True)
+    assert read_schema.model_validate(fetched_record) == new_data
+
+    fetched_record.name == "New name"
+
+    updated_fetched_record = await crud.upsert(async_session, fetched_record)
+    assert read_schema.model_validate(updated_fetched_record) == fetched_record
diff --git a/tests/sqlmodel/conftest.py b/tests/sqlmodel/conftest.py
index 0054b2d..85ad173 100644
--- a/tests/sqlmodel/conftest.py
+++ b/tests/sqlmodel/conftest.py
@@ -360,7 +360,7 @@ def client(
 
 
 @pytest.fixture
-def endpoint_creator() -> EndpointCreator:
+def endpoint_creator(test_model) -> EndpointCreator:
     """Fixture to create an instance of EndpointCreator."""
     return EndpointCreator(
         session=get_session_local,
diff --git a/tests/sqlmodel/crud/test_upsert.py b/tests/sqlmodel/crud/test_upsert.py
new file mode 100644
index 0000000..7fdaba2
--- /dev/null
+++ b/tests/sqlmodel/crud/test_upsert.py
@@ -0,0 +1,16 @@
+import pytest
+
+from fastcrud.crud.fast_crud import FastCRUD
+
+
+@pytest.mark.asyncio
+async def test_upsert_successful(async_session, test_model, read_schema):
+    crud = FastCRUD(test_model)
+    new_data = read_schema(id=1, name="New Record", tier_id=1, category_id=1)
+    fetched_record = await crud.upsert(async_session, new_data, return_as_model=True)
+    assert read_schema.model_validate(fetched_record) == new_data
+
+    fetched_record.name == "New name"
+
+    updated_fetched_record = await crud.upsert(async_session, fetched_record)
+    assert read_schema.model_validate(updated_fetched_record) == fetched_record