Aspects of natural history of the vine snake Oxybelis fulgidus from the northern region of Brazil were inferred based on the analysis of 106 preserved specimens (55 males and 51 females), and from a review of records in the published literature. Males mature at smaller size than females. Differences in body length and shape were also found among adult females and males: adult females are larger in mean snout-vent length and have relatively larger heads and shorter tails. Females have an extended seasonal vitellogenic cycle from April to December (mainly throughout the dry season). Oviductal eggs and egg-laying were recorded from September to December, while births occurred from January to April. Fecundity varied from four to twelve eggs or vitellogenic follicles (n = 13), and was positively correlated with female body length. Testicle volume is significantly larger from February to July (mainly in April and May; end of the rainy season), however the deferent ducts diameter do not differ significantly throughout the year. We hypothesized that both males and females may have an associated reproductive pattern, both synchronized in the end of the rainy season. Oxybelis fulgidus feeds on lizards (mainly iguanian) and passerine birds. Apparently, females feed more frequently on birds than males.