Utricularia reniformis is an endemic Brazilian carnivorous plant, most common in high-altitude grasslands. Knowledge of the reproductive biology of U.reniformis is essential for planning conservation strategies, but it is currently poorly understood. Thus, we studied the floral morphology, floral biology, breeding system and pollination of this species. U.reniformis produces and stores nectar in the flower spur, a classic feature of bee-pollinated flowers, and we recorded Xylocopa sp. and Bombus sp. as pollinators. Moreover, although it is self-compatible it is an obligate animal-pollinated species, as the sensitive stigma avoids self-pollination. However, in natural conditions reproductive success is low due to the rarity of visits from pollinators. We suggest that the low reproductive success caused by a deficit of pollinators may affect gene flow, causing loss of genetic diversity in U.reniformis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Polish Ministry of Science and Higher EducationFoundation for Polish Sciences (Start Programme)Univ Mogi das Cruzes, Lab Sistemat Vegetal, Mogi Das Cruzes, SP, BrazilUniv Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Sao Paulo, BrazilJagiellonian Univ, Dept Plant Cytol & Embryol, Krakow, PolandUNESP Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol Aplicada Agr, Lab Sistemat Vegetal, Jaboticabal, SP, BrazilUNESP Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol Aplicada Agr, Lab Sistemat Vegetal, Jaboticabal, SP, BrazilFAPESP: 08/52239-9