Abstract: Wheat and rice godowns in Pakistan have three to twelve years history of phosphine fumigation. Coleopterous adults and larvae from these godowns were collected, cultured and tested for phosphine resistance. Strains of Tribolium castaneum Hbst., Rhizopertha dominica F. and Trogoderma granarium Everts., exhibited varied levels of resistance, whereas all four strains of Sitophilus oryzae L. showed marginal resistance over the susceptible strain. Certain strains of R. dominica and T. castaneum were found to have 80-fold resistance. The possible causes of resistance and the methods of their control are discussed.