Background: The bivalve Aulacomya ater (cholga), is one of the most consumed mollusks by the population. However, there is evidence of fecal water contamination caused by causes that affect the sea, increasing the probability of contamination by the Cryptosporidium parvum, which generates cryptosporidiosis in people. Aim: To determine the presence of C. parvum in cholga extracted from the Bio Bio Region (Chile). Methods: Fifty-five cholgas were selected from a cultivation center and a natural extraction bank. These samples were processed in the laboratory and the presence of acid-alcohol resistant elements was evaluated. Positive samples were analyzed by direct immunofluorescence with anti-C. parvum antibody. Results: 16.4% of the total samples were affected by the oocysts of C.parvum. Conclusions: For the first time we described C. parvum in A. ater from the Chilean coast, being this mollusk a possible vehicle for transmission of cyptosporidiosis to the population and their predatory animals. Furthermore, the presence of C. parvum reflects fecal water contamination on the evaluated coasts. We are currently monitoring other extraction areas for this mollusk.