Cone snails have evolved an assortment of venom peptides as an evolutionary strategy for rapid prey immobilization and defence. Earlier studies estimated approximately 100 conopeptides per species. In this study we optimized liquid chromatography and electrospray ionization mass spectrometry for the detection of conopeptides in crude venom to characterize conopeptides present in the venom of individual specimens of Conus textile, C. imperialis and C. marmoreus. Using this approach, we have expanded the predicted number of venom peptides 10-fold to an estimate of 1000-1900 conopeptides per species. Our investigation has also revealed a surprisingly high level of intra-species variation that distinguishes cone snails from other venomous species including spiders and scorpions. Given this inherent diversity and variability, more sensitive bioassays and sequencing techniques will be required to fully explore conotoxin bioactivity.