Protein bait preferences of wasps ( Vespula vulgaris and V. germanica ) were determined by measuring the number of wasps attracted to different bait types, the amount of each bait type collected by wasps, and the proportion of wasps collecting bait. Fresh fish and meat baits attracted the largest number of wasps, but canned sardine cat‐food was collected in the greatest amounts. Factors influencing attraction of wasps to sardine cat‐food included wasp density, season, and weather. The number of wasps attracted to sardine cat‐food increased rapidly in January but lagged behind the number of wasps flying in and out of nests, peaked later, and declined earlier. The proportion of wasps that returned to nests carrying sardine cat‐food peaked in February‐March, when it was higher than the proportion collecting natural protein food. Sardine cat‐food is currently the best bait to use for wasp control because of its attractiveness, palatability, and acceptability to wasps. Future research should investigate other methods besides freezing for prolonging the shelf‐life of sardine cat‐food baits, and the use of solvent extracts of sardine cat‐food to prolong the field‐life of baits.