Phytoseiid mites play a crucial role in biological control programs. Developing efficient mass-rearing techniques for these mites is essential to enhance their applicability in large-scale management programs. This study aimed to develop and validate a simple mass-rearing protocol for the continuous production of generalist phytoseiid mites (Amblyseius swirskii, Neoseiulus californicus, and Neoseiulus barkeri). The rearing system consisted of a Petri dish placed on a water-saturated sponge in a plastic box containing water. Mites were fed a mixture of cattail pollen, rice husk, and Tyrophagus putrecentiae mites which were introduced into the rearing units three times a week. The prey mite was maintained in a similar system using yeast granules and rice husk as food. Population growth of the predatory mites was observed over an 8-week period under controlled laboratory conditions (25 ± 1 °C, 65 ± 5% RH, and 16L:8D photoperiod). The results showed that all three species successfully grew and overpopulated in the 6^th week, with 380.2 ± 16.7, 211.4 ± 12.9, and 283.9 ± 18.6 adult females of A. swirskii, N. californicus, and N. barkeri, respectively, being produced.  These values represent increases of 38, 21.1, and 28.3 times their respective initial population densities. A gradual decline in the phytoseiids population was observed in each unit following the sixth week. This suggests that the sixth week serves as a suitable time frame for subdividing the rearing units to maintain optimal population levels. The proposed rearing protocol turned out to be useful for the continuous production of the three test species, providing optimal conditions for population growth while preventing mites from escaping the box. This protocol offers a practical solution for the commercial mass production of generalist phytoseiids.