diff --git a/crc/api/workflow.py b/crc/api/workflow.py
index 82c83e23..1d7a509f 100644
--- a/crc/api/workflow.py
+++ b/crc/api/workflow.py
@@ -138,7 +138,9 @@ def delete_workflow_specification(spec_id):
     # Delete all events and workflow models related to this specification
     for workflow in session.query(WorkflowModel).filter_by(workflow_spec_id=spec_id):
         StudyService.delete_workflow(workflow.id)
-    session.query(WorkflowSpecModel).filter_by(id=spec_id).delete()
+    # the cascade feature doesn't work if
+    deleteSpec = session.query(WorkflowSpecModel).filter_by(id=spec_id).first()
+    session.delete(deleteSpec)
     session.commit()
 
 
diff --git a/crc/models/workflow.py b/crc/models/workflow.py
index 8230069b..1c586f05 100644
--- a/crc/models/workflow.py
+++ b/crc/models/workflow.py
@@ -4,6 +4,7 @@ import marshmallow
 from marshmallow import EXCLUDE,fields
 from marshmallow_sqlalchemy import SQLAlchemyAutoSchema
 from sqlalchemy import func
+from sqlalchemy.orm import backref
 
 from crc import db
 from crc.models.file import FileModel, FileDataModel
@@ -46,9 +47,9 @@ class WorkflowLibraryModel(db.Model):
    library_spec_id = db.Column(db.String, db.ForeignKey('workflow_spec.id'), nullable=True)
    parent = db.relationship(WorkflowSpecModel,
                                    primaryjoin=workflow_spec_id==WorkflowSpecModel.id,
-                                  backref='libraries')
+                                  backref=backref('libraries',cascade='all, delete'))
    library = db.relationship(WorkflowSpecModel,primaryjoin=library_spec_id==WorkflowSpecModel.id,
-                                  backref='parents')
+                                  backref=backref('parents',cascade='all, delete'))
 
 
 class WorkflowSpecModelSchema(SQLAlchemyAutoSchema):