diff --git a/pkg/training/repository.go b/pkg/training/repository.go
index d3e7974..6171f8d 100644
--- a/pkg/training/repository.go
+++ b/pkg/training/repository.go
@@ -74,6 +74,11 @@ func (r *InMemoryTrainingRepository) Update(training *Training) error {
 }
 
 func (r *InMemoryTrainingRepository) Delete(id TrainingID) error {
+	_, ok := r.trainings[id]
+	if !ok {
+		return ErrTrainingNotFound
+	}
+
 	delete(r.trainings, id)
 	return nil
 }