Boa constrictor was first documented on the island of Aruba in April of 1999. By the end of December, 2003, 273 B. constrictor had been captured. These snakes ranged in size from neonates (0.30 m total length) to large adults (2.8 m total length) and included at least two gravid females. Boa constrictor is currently distributed islandwide with the highest frequency of occurrence in the southern and southeastern portions of the island. The increasing frequency of occurrence, extensive distribution, and size diversity of B. constrictor indicate that a large, reproductively successful population is established on Aruba. The diet of the B. constrictor on Aruba was determined from the examination of stomach content and scat samples (N = 47). Birds comprised 40.4%, lizards 34.6% and mammals 25.0% of 52 separate prey items identified. A correlation was found between snake total length and prey mass (r₍₂₈₎ = 0.49, P < 0.01) suggesting an ontogenetic shift in the diet at a total length of approximately 1.0 m. In view of the diverse diet and increasing population of B. constrictor, there is concern about the potential impact of this invasive predator on the Aruban fauna. A government instituted euthanization program for all captured B. constrictor has proven ineffective at controlling the population.