Tetranychus urticae Koch (Acari: Tetranychidae) is an important pest causing economic losses in many cultivated crops worldwide. In the control of the pest, frequent insecticide/acaricide applications are preferred in the first place. However, factors such as the high reproduction rate and short life cycle of Tetranychus urticae make it easy to develop resistance to chemicals after a few applications. Wolbachia, Spiroplasma and Cardinium endosymbionts are found in many pest species including mites and cause different effects on the pest. In this study, pyridaben resistance in field populations of T. urticae and its relationship with detoxification enzymes were investigated. In addition, the presence of Wolbachia, Spiroplasma and Cardinium endosymbionts in Tetranychus urticae populations were investigated. Dry residue method was used to determine pyridaben resistance in T. urticae. In toxicity trials, 7 acaricide doses + 1 control group were used. Each group consisted of 3 replicates. In each replicate, there were 25 adult T. urticae individuals. Acaricides were applied as 2 mL on the leaf surface at a pressure of 1 atm using a spray tower. Dead-live counts of the populations were made after 72 hours. Pyridaben resistance ratios of Tetranychus urticae populations were determined by the ratio of LC₅₀ values of the field populations to LC₅₀ values of the susceptible population. The LC₅₀ value of pyridaben for the susceptible population GSS and an pesticide unexposed population were found to be approximately same around 10 mg/L. Compared to these populations, the highest resistance ratio were found to be 12.2 in Ca2 and Ce1 populations whereas Ca3 population had the lowest resistance ratio of 7.2 for field populations. In addition, high esterase and monoxygenase enzyme activities were determined in field populations of T. urticae. Wolbachia was found in all Tetranychus urticae populations at varying frequencies and Cardinium endosymbiont was found in only six of seventeen populations. Wolbachia endosymbiont found in the mite populations were found to be two haplotypes differing at a single SNP loci for 650bp wsp gene. In contrast, the presence of a Spiroplasma endosymbiont was not identified in any of the T. urticae populations tested.