Background: Anisakis simplex, a fish and cephalopodes parasite, can cause either gastrointestinal symptoms or allergic reactions in humans on eating/handling contaminated fish. Objective: The aim of our study was to determine the capacity of Anisakis simplex to induce specific IgE production and allergic reactions following eating and handling fish in a population at risk. Methods: We determined the levels of total IgE, specific IgE, and eosinophil count in 28 fishermen/fishmongers (group A) and 15 healthy donors (group B). A skin prick test (SPT) with extracts from Anisakis and the most common species of fish in our country, were also carried out. Results: Specific IgE to Anisakis were found in 14 subjects of group A (13 of them had a positive SPT to the same extract) and none of group B (only one subject had a positive SPT). The SPT with fish extracts was positive in 4 patients of group A but in none of group B. Subjects in group A with specific IgE to Anisakis showed higher total IgE levels and eosinophil counts compared with either other individuals of the same group or to those of group B. Conclusions: These results indicate that fishermen/fishmongers are a population at risk for Anisakis simplex sensitization and suggest that this kind of sensitization should also be investigated not only in subjects like fishermen/fishmongers who live in countries where fish is likely to be contaminated with Anisakis simplex parasites, but also in those who handle fish for other reasons.