Experiments on protection of corn seeds in multiwall kraft paper bags (3-ply) with phosphine took place in Campinas, São Paulo State, Brazil, to investigate the control of infestations of the maize weevil Sitophilus zeamais Mota. It was concluded that corn seeds in kraft paper bags may be normally fumigated with phosphine as in cotton bags. There was no difference between phosphine released from national (Gastoxin B) or imported (Gastoxin and Phostoxin) products. However, usual dosages of phosphine must be increased due to indication resistance of & zeamaiz to this fumigant.