Soybean molasses was evaluated as a partial replacement for sugarcane molasses as a carbon source for biofloc development in the super intensive culture of Pacific white shrimp (Litopenaeusvannamei). A 50-day study was conducted with juvenile (3.2 g) shrimp stocked in 16 800 Ltanks at a stocking density of 250 shrimp m3.Control of total ammonia concentration was per-formed by the addition of combined mixtures of soybean and sugarcane molasses to the culture water. Three different molasses treatments were evaluated using different soybean-to-sugarcane molasses ratios: 15–85%, 38–62% and 60–40%respectively. The control group was treated only with sugarcane molasses. Water quality, chlorophyll a concentration, heterotrophic bacterial load, Vibrio spp. concentration and zoo technical indexes were all evaluated. Total ammonia con-centration was controlled by heterotrophic and chemotrophic pathways. Biofloc formation, asquan tified by measuring the total suspended solids, was not altered. The Vibrio spp. concentration showed a significant reduction in treatments with soybean-to-sugarcane molasses ratios of 38–62% and 60–40%. All combined mixtures of soybean and sugarcane molasses could main-tain water quality and productivity in the super-intensive culture of L. vannamei using the bioflocsystem. Thus, the potential use of a residue from agro industry as a carbon source in a biofloc culture is demonstrated.