Ten different two-spotted spider mite (Tetranychus urticae Koch) populations were collected from greenhouses in two geographically different regions of Turkey, Antalya and Isparta. Individual spider mites were homogenized in microplates using multi-homogenizer, and the genetic variations in the esterase of these populations were studied by nondenaturing polyacrylamide gel electrophoresis. The results showed that esterase enzymes were polymorphic in all populations in both regions. However more intrapopulation and interpopulation variations were observed in the population from Antalya region.