The European mink (Mustela lutreola) is listed as a critically endangered species because of ongoing population reduction from habitat degradation and the effects of introduced species, such as American mink (Neovison vison). This small, fragmented population becomes vulnerable to many other threats, including diseases. Leishmaniosis is a zoonotic disease caused by the protozoan parasite Leishmania infantum found in the Mediterranean area, which affects many mammals, including wild small mammals. Furthermore, clinical disease caused by L. infantum has recently been described in other mustelids. To assess the exposure to Leishmania sp. infection in mink species in northern Spain, blood samples from 139 feral American mink and 42 native European mink from north Spain were evaluated for Leishmania sp. infection using enzyme-linked immunosorbent assays against Leishmania spp. antibodies, with 52.4% of American mink and 45.3% of European mink being found seropositive. This finding raises questions regarding how the disease may affect these species and the potential repercussions for conservation efforts. Despite a high seroprevalence being observed in wild mink of both species in this study, association with clinical or pathologic signs of disease has yet to be elucidated.