Technical Abstract: A one percent boric acid - sucrose water bait was evaluated for efficacy against structural infestations of Pharaoh ants, Monomorium pharaonis (L.). One of the study sites was an apartment complex with a natural infestation of Pharaoh ants. The other site consisted of a group of small buildings, which were purposely infested with Pharaoh ants. Treated and untreated (control) bait stations were replaced once a week for three weeks at each site and then removed from the study. Significant reductions in the number of foraging ants at both sites were attained in the first week after exposure to the boric acid bait and was maintained thereafter for seven weeks in the apartment complex and eight weeks in the small building complex.