Oligonychus punicae (Hirst) (Trombidiformes:Tetranychidae) is a common pest in Mexican avocado orchards. Neoseiulus californicus (McGregor) (Mesostigmata: Phytoseiidae) is frequently found associated with avocado orchards in Mexico and may be an important aid for controlling O. punicae. Given the lack of information in the scientific literature, this study evaluated the predation and oviposition of N. californicus when fed O. punicae at different developmental stages in a no-choice experiment. We also assessed fluctuations in the population size of O. punicae and N. californicus in commercial avocado orchards; correlations among mite density and air temperature, humidity, and precipitation in commercial avocado orchards; and the correlations between prey and predator populations. The no-choice test revealed that N. californicus adult females fed on O. punicae of all developmental stages, with higher levels of predation being recorded for eggs, followed by larvae. The highest oviposition values of N. californicus females were observed when females were fed O. punicae eggs. In orchards, the populations of both mites increased between February and June. The populations peaked during the warmest months of the year, with O. punicae populations peaking between June and July and N. californicus peaking in August. In addition, the population size of N. californicus was significantly and positively correlated with rainfall, air temperature, and the population densities of O. punicae. Meanwhile, O. punicae population size was positively correlated with air temperature, and the population of its predator N. californicus.