The effects of entomopathogenic isolates, Isaria farinosa (Holm.) and Beauveria bassiana (Balsamo) Vuillemin (Sordariomycetes: Hypocreales), were investigated on the adult stages of Aelia rostrata Boh. (Hemiptera: Pentatomidae) under of 70% and 95% relative humidity and with 1x10(6) and 1x10(8) conidial concentration (ml(-1)). These experiments were conducted in a climatic chamber with 27 +/- 1 degrees C and 16 h. light and 8 h. dark photoperiod, and the mortality percentages were determined in the 6th, 9th and 12th days of incubation. The result of experiments showed that both of the entomopathogens were more effective in 95% R.H. and 1x10(8) conidial concentrations (ml(-1)). At 70% R. H. and 1x10(8) conidial concentrations (ml(-1)), while I. farinosa caused 70% mortality in the 12th day of incubation, B. bassiana caused 100% mortality in the 9th day of incubation. It was concluded that B. bassiana isolate was more effective than I. farinosa isolate on wheat stink bug, A. rostrata.