Adult female mink (Mustela vison) were fed a diet that contained Fusarium moniliforme culture material that provided dietary concentrations of 89 ppm fumonisin B1, 21 ppm fumonisin B2, and 8 ppm fumonisin B3 for 87 days. During the trial, there was mild lethargy in the mink fed fumonisins, but no other clinical signs or differences in feed consumption (measured during the first two weeks), body weights, or survivability were observed between the fumonisin-treated and control mink. Several hematologic parameters (mean corpuscular hemoglobin concentration, plasma total solids, and lymphocyte concentration) and serum chemical concentrations (globulin, phosphorus, potassium, blood urea nitrogen, creatinine, bilirubin, and cholesterol) and activities (alkaline phosphatase, alanine aminotransferase, amylase, and aspartate aminotransferase) were greater in the mink fed fumonisins than in the controls. Serum albumin/globulin and sodium/potassium ratios and chloride concentrations were lower in the fumonisin-fed mink than in the controls. The concentrations of free sphinganine and the ratio of free sphinganine to free sphingosine in the liver and kidneys of the fumonisin-treated mink were greater than in the control mink. No histopathologic alterations were associated with fumonisin treatment. These results indicate that long-term dietary exposure to F. moniliforme culture material containing 118 ppm total fumonisins is not lethal to adult mink, but can produce adverse physiological effects in the animals.