Investigations on bioefficacy of parasitoids and microbial agents against potato tubermoth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) were carried out under field and storage conditions of potato during 1996-1997. The results showed that three sprays of endosulfan 0.05 per cent at 10 days interval proved to be the most effective and on par with four releases of Chelonus blackburni Cameron [@] 15000 adults/ha/release at weekly interval, Copidosoma koehleri Blanchard [@] 50000 adults/ha/release and Trichogramma chilonis Ishii [@] 50000 adults/ha/release at weekly interval, and three sprays of Bacillus thuringiensis Berliner [@] 1 kg/ha at 10 days interval. Amongst the parasitoids, maximum parasitism was recovered through retrieval with C. blackburni (71.78%), followed by C. koehleri (69.39%) and T. chilonis (61.33%). Under storage conditions (Arnies), initial release of C. blackburni [@] 2 adults/kg tubers recorded minimum tuber infestation (7.21%) after 60 days. none