Ochratoxin A has been obtained from both mycelium and culture filtrates of Penicillium viridicatum Westling grown on a yeast extract – sucrose medium. Ergosterol was also identified as a metabolite. The greatest amount of ochratoxin A was detected 9 days after inoculation. Toxin production decreased greatly after several successive subcultures. However, it was possible to obtain a strongly toxinogenic isolate again from the parent culture. Small amounts of ochratoxin A were detected in 60% whole wheat bread slices used as a substrate for P. viridicatum.