Soybean molasses was evaluated as a partialreplacement for sugarcane molasses as a carbonsource for biofloc development in the superinten-sive culture of Pacific white shrimp (Litopenaeusvannamei). A 50-day study was conducted withjuvenile (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 ofsoybean and sugarcane molasses to the culturewater. Three different molasses treatments wereevaluated using different soybean-to-sugarcanemolasses ratios: 15–85%, 38–62% and 60–40%respectively. The control group was treated onlywith sugarcane molasses. Water quality, chloro-phyll a concentration, heterotrophic bacterialload, Vibrio spp. concentration and zootechnicalindexes were all evaluated. Total ammonia con-centration was controlled by heterotrophic andchemotrophic pathways. Biofloc formation, asquantified by measuring the total suspendedsolids, was not altered. The Vibrio spp. concen-tration showed a significant reduction in treat-ments with soybean-to-sugarcane molasses ratiosof 38–62% and 60–40%. All combined mixturesof 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 fromagroindustry as a carbon source in a biofloc cul-ture is demonstrated.