Diel oviposition patterns of Anopheles bellator were determined for field collected females from Platanal Forest, Cumaca, Trinidad. The time of oviposition and number of eggs laid were monitored at two-hour intervals for a set of 30 individual females and a group of 120 females. Individual females of An. bellator displayed bimodal nocturnal patterns of oviposition. During the first gonotrophic cycle, two waves of oviposition occurred between 1600 and 2400 h (80.9% of eggs laid; 78% of occurrences) and between 0200 and 0600 h (19.1% of eggs laid; 22% of occurrences). During the second gonotrophic cycle the oviposition pattern was similar to that observed during the first gonotrophic cycle, except that oviposition ended at 0400 h rather than at 0600 h. A similar oviposition pattern was observed among the 120 caged adults as found during the second gonotrophic cycle of individual females. The length of the gonotrophic cycle ranged from 57 to 120 hours (mean 72.3 hours) for the first gonotrophic cycle and from 61 to 78 hours (mean 70.3 hours) for the second cycle. The fecundity of An. bellator averaged 56.6 +/- 25.0 (range 13 to 101 eggs) and 39.3 +/- 13.3 (range 23 to 59 eggs) for the first and second gonotrophic cycles, respectively. Females survived in the laboratory for a maximum of 19 days. These observations on An. bellator oviposition patterns are the first to be described and may be useful for future attempts at colonization.