This study investigated mite biodiversity and density on Capsicum annuum in temperate (Bursa and Yalova provinces) and semi-arid (Ankara province) zones of Turkey from 2009 to 2010. A total of twenty-six phytophagous, predatory and generalist mite species were established on pepper leaves. Tetranychus urticae (Tetranychidae) was the single predominant species on the plants in all zones, while Phytoseius plumifer, Neoseiulus californicus (Phytoseiidae) and Tarsonemus bifurcatus (Tarsonemidae) were found to be other common species. Mite diversity and density were higher in temperate zone provinces than in Ankara, which has semi-arid conditions. This variation was significantly correlated with high humidity in the temperate zone, but only for phytophagous mites. The highest number of predatory species was found in the temperate zone, a finding also correlated with humidity, but not significantly. Although phytophagous mite diversity was lower than that of predatory mites in both zones, phytophagous mites were more than abundant than both predatory and generalist mites. The current study observed a significantly high population density of T. urticae from late July to mid August of 2010 and 2011. The sharp decline in T. urticae density on pepper was found to be associated with the onset of rainfall in June and September. Consequently, similar population growth patterns in phytoseiids [Neoseiulus bicaudus, N. californicus and Typhlodromus (Anthoseius) recki in Bursa and Yalova; Phytoseius plumifer in Ankara] were found in all zones and in both years. Generally, predatory mite density showed a gradually increasing population growth pattern from late July to early October.