Even after obj.save(), the obj still does not have an id, so I cannot access or manipulate the m2m records. Just keep getting a "instance needs to have a primary key value before a many-to-many relationship can be used" error. def save_model(self, request, obj, form, change): obj.save() # this doesn't work super(Table2Admin, self).save_model(request, obj, form, change) # still doesn't save for tb1 in obj.table1.all: tb1_obj = ThroughTable.objects.get(table1=bk, table2=obj) # do other stuff What am I doing wrong? Why do I need to do to save this model?