diff --git a/backend/service/services.py b/backend/service/services.py
index dbeb840..ab7b884 100644
--- a/backend/service/services.py
+++ b/backend/service/services.py
@@ -1,5 +1,7 @@
+from backend.model.student import Student
 from backend.model.tribe import Tribe
 from backend.repository.abstract_repository import AbstractRepository
+from backend.repository.student_sqlite_repository import StudentRepositoryError
 from backend.repository.tribe_sqlite_repository import TribeRepositoryError
 
 
@@ -7,7 +9,15 @@ class TribeExists(Exception):
     pass
 
 
-class TribeDosNotExists(Exception):
+class TribeDoesNotExist(Exception):
+    pass
+
+
+class StudentExists(Exception):
+    pass
+
+
+class StudentDoesExist(Exception):
     pass
 
 
@@ -26,7 +36,7 @@ def update_tribe(name: str, level: str, tribe_repo: AbstractRepository, conn) ->
     try:
         tribe_repo.update(name=name, tribe=tribe)
     except TribeRepositoryError:
-        raise TribeDosNotExists(f"The tribe {name} does not exists you can't update it")
+        raise TribeDoesNotExist(f"The tribe {name} does not exists you can't update it")
     conn.commit()
     return tribe
 
@@ -35,6 +45,32 @@ def delete_tribe(name: str, tribe_repo: AbstractRepository, conn) -> None:
     try:
         tribe_repo.delete(name=name)
     except TribeRepositoryError:
-        raise TribeDosNotExists(f"The tribe {name} does not exists you can't delete it")
+        raise TribeDoesNotExist(f"The tribe {name} does not exists you can't delete it")
 
     conn.commit()
+
+
+def add_student(
+    name: str,
+    tribe: str,
+    student_repo: AbstractRepository,
+    tribe_repo: AbstractRepository,
+    conn,
+) -> Student:
+
+    try:
+        _tribe = tribe_repo.get(tribe)
+    except TribeRepositoryError:
+        raise TribeDoesNotExist(
+            f"The tribe {tribe} does not exists. Can't add a student in it"
+        )
+
+    student = Student(name=name, tribe=_tribe)
+
+    try:
+        student_repo.add(student)
+    except StudentRepositoryError:
+        raise StudentExists(f"The student {student.name} already exists. Can't add it.")
+
+    conn.commit()
+    return student
diff --git a/tests/unit/test_service.py b/tests/unit/test_service.py
index 523e856..ec91c30 100644
--- a/tests/unit/test_service.py
+++ b/tests/unit/test_service.py
@@ -6,8 +6,8 @@ from backend.repository.abstract_repository import AbstractRepository
 from backend.repository.student_sqlite_repository import StudentRepositoryError
 from backend.repository.tribe_sqlite_repository import TribeRepositoryError
 from backend.service import services
-from backend.service.services import TribeDosNotExists, TribeExists
-from tests.model.fakes import build_tribes
+from backend.service.services import StudentExists, TribeDoesNotExist, TribeExists
+from tests.model.fakes import build_student, build_tribes
 
 
 class FakeTribeRepository(AbstractRepository):
@@ -34,7 +34,7 @@ class FakeTribeRepository(AbstractRepository):
         try:
             return self._tribes[name]
         except KeyError:
-            raise TribeRepositoryError(f"The tribe {tribe} does not exists")
+            raise TribeRepositoryError(f"The tribe {name} does not exists")
 
     def delete(self, name: str) -> None:
         try:
@@ -50,7 +50,8 @@ class FakeStudentRepository(AbstractRepository):
     def add(self, student: Student) -> None:
         if student.id not in self._students.keys():
             self._students[student.id] = student
-        raise StudentRepositoryError(f"{student} already exists")
+        else:
+            raise StudentRepositoryError(f"{student} already exists")
 
     def update(self, id: str, student: Student) -> None:
         try:
@@ -93,7 +94,7 @@ def test_add_tribe():
         name=tribe.name, level=tribe.level, tribe_repo=tribe_repo, conn=conn
     )
 
-    assert conn.committed == True
+    assert conn.committed is True
     assert tribe_repo.list() == [tribe]
 
 
@@ -125,7 +126,7 @@ def test_update_tribe():
         name=tribes[0].name, level=other_level, tribe_repo=tribe_repo, conn=conn
     )
 
-    assert conn.committed == True
+    assert conn.committed is True
     assert set(tribe_repo.list()) == set(tribes)
 
 
@@ -134,7 +135,7 @@ def test_update_tribe_fail_not_exists():
     tribe_repo = FakeTribeRepository(tribes)
     conn = FakeConn()
 
-    with pytest.raises(TribeDosNotExists):
+    with pytest.raises(TribeDoesNotExist):
         services.update_tribe(
             name="azerty", level="jkl", tribe_repo=tribe_repo, conn=conn
         )
@@ -150,7 +151,7 @@ def test_delete_tribe():
     tribe = tribes.pop()
     services.delete_tribe(name=tribe.name, tribe_repo=tribe_repo, conn=conn)
 
-    assert conn.committed == True
+    assert conn.committed is True
     assert set(tribe_repo.list()) == set(tribes)
 
 
@@ -159,7 +160,54 @@ def test_delete_tribe_fail_not_exists():
     tribe_repo = FakeTribeRepository(tribes)
     conn = FakeConn()
 
-    with pytest.raises(TribeDosNotExists):
+    with pytest.raises(TribeDoesNotExist):
         services.delete_tribe(name="azerty", tribe_repo=tribe_repo, conn=conn)
 
     assert conn.committed == False
+
+
+def test_add_student():
+    tribes = build_tribes(1)
+    tribe_repo = FakeTribeRepository(tribes)
+    student = build_student(tribes, 1)[0]
+    student_repo = FakeStudentRepository()
+    conn = FakeConn()
+
+    saved_student = services.add_student(
+        name=student.name,
+        tribe=student.tribe.name,
+        student_repo=student_repo,
+        tribe_repo=tribe_repo,
+        conn=conn,
+    )
+
+    assert conn.committed is True
+
+    listed_student = student_repo.list()[0]
+
+    assert student.name == listed_student.name
+    assert student.tribe.name == listed_student.tribe.name
+    # The id is not passed to the service, they can't have the same.
+    assert student.id != listed_student.id
+
+    assert saved_student == listed_student
+
+
+def test_add_student_tribe_doesnt_exist():
+    tribes = build_tribes(1)
+    tribe_repo = FakeTribeRepository(tribes)
+    students = build_student(tribes, 1)
+    student_repo = FakeStudentRepository()
+    conn = FakeConn()
+
+    student = students[0]
+    with pytest.raises(TribeDoesNotExist):
+        services.add_student(
+            name=student.name,
+            tribe="iuouiouiouio",
+            student_repo=student_repo,
+            tribe_repo=tribe_repo,
+            conn=conn,
+        )
+
+    assert conn.committed is False