Current trapping systems for Anastrepha fruit flies utilize a two-component attractant consisting of ammonium bicarbonate and putrescine. Though ammonia-based lures have been highly effective for some tephritids (e.g. Mediterranean fruit fly, Ceratitis capitata), attraction of Anastrepha species has been variable. The need for improved lures prompted a research approach using electroantennography (EAG) to examine response of antennal olfactory receptors to potential volatile attractants. In this study, we measured EAG response of sexually mature Caribbean fruit flies, A. suspensa (Loew), to commercially available lures of ammonium bicarbonate and putrescine. Chemical samples were delivered in known quantities, as determined by Fourier transform infrared (FTIR) spectroscopic analysis. EAG measurements were then used to construct dose-response curves for ammonium bicarbonate and putrescine, presented separately and in combination. For both lures, mean EAG response of females was greater than response of males. For both sexes, ammonium bicarbonate generated a much larger amplitude response than putrescine. When the two lures were combined, the antennal response was greater than that elicited by either lure alone. This additive effect suggests that multiple olfactory receptor types may be involved in the chemoreception of ammonium bicarbonate and putrescine.