Hexythiazox resistance in a Neoseiulus californicus population selected in laboratory conditions was analyzed in the present study. LC50 and LC60 values of N. californicus were determined via the leaf disk method using a spray tower. Resistance ratios were determined by dividing the LC50 values of selected populations to the LC50 value of the laboratory population. Resistance ratio was increased to 64.04 -fold in selected population (named HEX14) after 14 selection cycles with hexythiazox. The effects of PBO, IBP and DEM were examined on hexythiazox resistance. Furthermore, glutathione S-transferase, cytochrome P450 monooxygenases and acetylcholinesterase enzymes were determined using kinetic methods and esterase enzyme was determined using electrophoretic and kinetic methods in laboratory and HEX14 populations. The study conducted with PBO, IBP and DEM in the HEX14 population showed that synergistic effect rates were 1.71, 3.25 and 1.98 -fold, respectively. The cross resistance ratios of the HEX14 population to spirodiclofen, etoxazole, spiromesifen, propargite, clofentezine and milbectin were 8.12, 14.41, 17.96, 17.48, 12.67 and 11.22 -fold, respectively. The hexythiazox resistance of the HEX14 population was incompletely dominant and monogenic. A 3.27 -fold esterase, 2.35 -fold GST and 2.02 -fold cytochrome P450 monooxygenase and 3.34 -fold AChE enzyme activity were detected in the HEX14 population in biochemical assays.