This work was conducted to determine the effect of yeast food on biology of the acarid mites; Caloglyphus berlesi (Michael), Caloglyphus mycophagous (Megnin), Rhizoglyphus robini Clapared and Tyrophagous longior (Cervais) under the laboratory condition at 26 ± 2°C and 70 % R.H. The generation time significantly differed among different female species (F_3,67 = 159.83; P < 0.05). Tyrophagous longior had significantly the longest generation time with average 19.05 days. followed by Caloglyphus berlesi 14.83 days and Rhizoglyphus robini 14.64 days: while Caloglyphus mvcophagous showed significantly the sho1test generation time with average 9.81  days. Likewise, there were significant differences among different species in daily rate of eggs per female (F_3,76 = 21.697; P < 0.05).  Caloglyphus mycophagous exhibited the highest average daily rate 25.51 eggs, followed by Caloglyphus berlesi with 19.80 eggs, then Tyrophgous longior with average 15.82  eggs. The last species was Rhizoglyphus robini, with the lowest average daily rate 8.38 eggs. Therefore, Caloglyphus mycophagous is considered the most dangerous species as its generation time  was the shortest  and with highest daily rate. So it, gave very large of population.