This study determined the side effects of a selection of pesticides on the eggs, nymphs and adults of the predatory mite Neoseiulus californicus. It assessed the acaricides spirodiclofen, cyhexatin, hexythiazox and clofentezine; the insecticides indoxacarb, chlorantraniliprole, diflubenzuron and pyriproxyfen; and the insecticide/acaricides abamectin and spiromesifen. A spray tower-leaf disk method was used to determine the side effects of pesticides on N. californicus. Three doses of each pesticide were applied: a field application dose (T), half of the field application dose (T/2) and double the field application dose (2T). Dead-live counts were made at days 1, 3, 5 and 7 after application. Daily observations were made during egg applications to observe whether the eggs were hatching. None of the pesticides, except for hexythiazox, showed any effect on the eggs of predatory mites. At the 2T dose, chlorantraniliprole and hexythiazox were harmless, and cyhexatin and pyriproxyfen were found to be slightly harmful to N. californicus nymphs and adults. At T and T/2 doses, all of the pesticides except abamectin were found to be harmless to nymphs. Abamectin was harmful at all doses to nymphs. At the T and T/2 doses in adults, chlorantraniliprole, indoxacarb and diflubenzuron were harmless; clofentezine, cyhexatin, spiromesifen, spirodiclofen and pyriproxyfen were slightly harmful; and abamectin was harmful and moderately harmful, respectively. The effect of pesticides varies with predatory mite stages.