ABSTRACT. Silva O.R., Andriotti P.A., Leal L.C.S.R. & Bittencourt A.J. [Biology of immature stages of Stomoxys calcitrans (Diptera: Muscidae) in sugarcane and vinasse.] Biologia de estágios imaturos de Stomoxys calcitrans (Diptera: Muscidae) em cana de açúcar e vinhoto. Revista Brasileira de Medicina Veterinária, 37(Supl.1):45-50, 2015. Departamento de Medicina e Cirurgia Veterinária, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, BR 465, Km 7, Seropédica, RJ 23897-970, Brasil. E-mail: email@example.com To evaluate the effect of vinasse associated with sugarcane in the preoviposition, oviposition and immature stages of S. calcitrans, flies were collected, divided into groups of 15 (six cages) and maintained in BOD (26.5±1°C/80% RH). The rearing media (77g of cane) was deposited into beaker and stored for three days of fermentation. The vinasse was added in proportions of 1Kg/2L, 1kg/1L and 1Kg/0.5L; Groups I, II and III, and a Control (water) for each group with vinasse. The adults were exposed to vinasse in cages, containing blood, water and 10g of the diet. The eggs were deposited in Petri dishes with moistened filter paper (0.5mL distilled water) and a drop of blood. The hatched larvae (24h) were counted and transferred to beakers containing diet. On the tenth day, the L3 were counted, weighed and returned to the diet. The pupae were removed on the 15th day post-oviposition and deposited in Petri dishes into the cage for emergence of adults. The preoviposition lasted four days and oviposition in Groups I (16 days) and II (20 days) was longer when compared to Group III (11 days). Larval viability showed how critical this stage is, as at the highest concentration of vinasse, viability was lower than in its control (Group I-2.4%/Control I-29%). Fungal contamination occurred in Group II, affecting larval viability (0.51%) and the following stages, being lower than its control (8.75%). In Group III (19.35%) there was almost no difference from the control (19.3%), showing that in diets with less vinasse, the influence would be small or null. Pupal viability rose as the vinasse level in the diet decreased (Group I-66.6%; Group III-83.3%), except in Group II (50%). The pupal period was longer in the groups with vinasse, which may be related to toxic substances that would retard the emergence of adults.