Abstract: A machine for automatically filling and sealing large bulk thermoplastic bags which includes: a framework with a base and a backplane having an integral sliding carriage; a pneumatically controlled filling spout which holds the bag open for filling; a pneumatically controlled finger mechanism which aligns the bag for sealing; and a pneumatically controlled sealing mechanism which comprises a mounting arm, a guide rail, a first and second pneumatic cylinder and a heat sealing assembly. The heat sealing assembly uses electrically heated pads and pressure to seal the upwardly open end of a thermoplastic bag after it has been filled.