Strains Inaba 569B and Ogawa B1307 of Vibrio cholerae were grown in shaken Casamino Acids-yeast extract-glucose medium at 30 and 37 C for 4 days. Time courses of production of neuraminidase (NM), mucinase (MC), proteinase (PR), lytic factor (LF), and vascular permeability factor (PF) were compared by examining culture filtrates taken at various intervals. With both strains, turbidities were generally higher at 30 C than at 37 C. Both strains showed marked cellular lysis after maximal growth was attained at 48 hr at both temperatures. NM and PF were early products, maximal yield being attained within 24 hr. At 37 C, the peak of NM reached at about 10 hr was higher than at 30 C, but disappeared more quickly. The yield of PF was greater at 30 C than at 37 C, and 569B produced more PF. With 569B, PF appeared during the exponential phase, but continued to increase substantially after this phase terminated. At 30 C, the peak attained at 24 hr by 569B was well maintained until 96 hr, but fell moderately at 37 C. In contrast, with B1307 PF fell sharply and virtually disappeared after 24 hr at both temperatures, with concomitant rise in late products. PR and LF were late products; neither was detected in 569B filtrates, whereas older cultures of B1307 showed high levels of both enzymes. MC was an early product with 569B, resembling PF, whereas it was a late product with B1307.