In this paper the Latin American species of the water mite genus Torrenticola are presented and discussed comprehensively for the first time. All 21 previously known species from Central and South America are portrayed in detail, descriptions are given for 36 new species from Costa Rica: Torrenticola adunca, T. alargada, T. alexandra, T. alticola, T. altifontana, T. amalgamada, T. ambigua, T. australis, T. baderi, T. chicacoxalis, T. chirripoensis, T. collina, T. conopalpis, T. corta, T. cortobrazo, T. costaricense, T. cumbrensis, T. delgada, T. dispersa, T. elhachensis, T. esferica, T. esquinada, T. fastigata, T. flexirostris, T. fontinale, T. guanacastensis, T. harpagophora, T. levicoxalis, T. menudopalpis, T. monticola, T. pervagata, T. rapidensis, T. ratoncitoi, T. rubella, T. tilaranensis and T. torpebrazo . The Latin American species of Torrenticola are subdivided in a clear, robust system of ten species groups – five of these are regarded as phylogenetic entities, five as rather artificial groups. An identification key to these species groups is given, as well as keys, measurement tables, figures and detailed descriptions of all species within these groups. The males of T. gennada Cook, 1980 and T. keesdavidsi Cramer, 1992, as well as the female of T. amala Cook, 1980 are described for the first time. Descriptions and figures of the genital skeleton of nine formerly described species are given for the first time. All information available on the habitat preferences (habitat type, stream velocity, altitudinal distribution, choriotope types, temperature and conductivity) and the geographical distribution of the species is presented. Zoogeographical characteristics, endemicity and habitat preferences of the 42 species of Torrenticola found in Costa Rica are analysed. The main object of this study is to facilitate further systematic and ecological work on this important genus and to make it accessible for general limnological surveys.