Soybean (Glycine max (L.): Fabaceae) is considered the most important agricultural crop in Brazil. Phytophagous tetranychid mites such as Mononychellus planki McGregor, Tetranychus ludeni Zacher, and T. urticae Koch are considered pests of soybean crops. Neoseiulus idaeus Denmark & Muma (Phytoseiidae) is a predatory mite of T. ludeni and T. urticae. This study aimed at analyzing the feeding preference of N. idaeus among three types of prey (M. planki, T. ludeni, and T. urticae), its prey-stage preference, and its predation rate under controlled conditions. During immature stages of N. idaeus, we carried out observations to monitor predator survival and to ensure food availability (eggs and different prey stages) throughout the study period. Neoseiulus idaeus preferred T. urticae compared to T. ludeni and M. planki, and it preferred T. ludeni compared to M. planki. This predator preferred T. urticae and T. ludeni when compared to leaves without prey; however, when analyzed with M. planki and leaves without prey, it showed no preference. Regarding oviposition site, T. urticae was preferred over T. ludeni or M. planki. However, between T. ludeni and M. planki, N. idaeus preferred T. ludeni. This predator preferred to oviposit where T. urticae and T. ludeni were located instead of leaves without prey. However, when it was assessed with M. planki and on dry leaves without prey, there was no preferred oviposition site. These results show a strong preference for T. urticae as food; however, in the absence of this prey, N. idaeus feeds on T. ludeni and M. planki. In all immature stages and as adults, N. idaeus preferred T. urticae eggs. In protonymphal, deutonymphal, and adult stages it also consumed prey larvae and nymphs. Only adult N. idaeus consumed adult prey. The total predation rate for eggs, larvae, nymphs, and adults of T. urticae was 55.9%, 14.34%, 22.11%, and 7.65%, respectively. The average lifespan of females of this predator was 16.07 days, when they consumed 3.05 prey/female/day. These results suggest that N. idaeus has potential to be used in an applied biological control program for T. urticae.