Black peppercorns supported the growth of Aspergillus parasiticus (flavus) NRRL 3145. Incubation at 28 C and RH of 85% for 30 days resulted in profuse conidial production on the reticulate ridges of the peppercorns. An SEM study of these ridges showed that they were cortical eruptions, and the particulate matter present favored mycelial establishment. Hyphal anastamoses were commonly observed. Following this incubation the inoculated peppercorns were stored in the dark at room temperature and ambient humidity for 15 days. Aflatoxin was detected on a minicolumn. Aflatoxin B₁ was produced at levels of 60 g/kg with traces of aflatoxins B ₂, G₁ and G₂. Quantitative estimation was based on a visual comparison with standards by thin-layer chromatography.