diff --git a/backend/app/coordinator/routes/enrollments.py b/backend/app/coordinator/routes/enrollments.py
index 19fcf56..8429c77 100644
--- a/backend/app/coordinator/routes/enrollments.py
+++ b/backend/app/coordinator/routes/enrollments.py
@@ -28,6 +28,15 @@ def create_enrollments(examination_schedule_id: int, data: dict) -> dict:
     if start_date.date() != end_date.date():
         abort(400, "Invalid dates! Only hours can be different!")
 
+    enrollment = Enrollment.query.filter(Enrollment.start_date >= start_date,
+                                         Enrollment.start_date < end_date).first()
+    if enrollment is not None:
+        abort(400, "You have just created enrollments for this range date!")
+
+    enrollment = Enrollment.query.filter(Enrollment.end_date > start_date, Enrollment.end_date <= end_date).first()
+    if enrollment is not None:
+        abort(400, "You have just created enrollments for this range date! `1")
+
     delta = end_date - start_date
     delta_in_minutes = delta.total_seconds() / 60
     if delta_in_minutes % prt != 0:
@@ -37,9 +46,9 @@ def create_enrollments(examination_schedule_id: int, data: dict) -> dict:
     enrollments = []
     for i in range(amount):
         sd = start_date + datetime.timedelta(minutes=i * prt)
-        ed = start_date + datetime.timedelta(minutes=(i + 1) * prt)
-        enrollment = Enrollment(start_date=sd, end_date=ed, examination_schedule_id=examination_schedule_id)
-        enrollments.append(enrollment)
+    ed = start_date + datetime.timedelta(minutes=(i + 1) * prt)
+    enrollment = Enrollment(start_date=sd, end_date=ed, examination_schedule_id=examination_schedule_id)
+    enrollments.append(enrollment)
     db.session.add_all(enrollments)
     db.session.commit()