Visible moulds were isolated and identified from 102 samples of each of the Norwegian types of semi-hard cheeses called Norvegia and Jarlsberg. Penicillium species made up 98.1 and 89.2% of the isolates from the Jarlsberg and Norvegia cheeses, respectively. The most frequently occurring species on both was P. roqueforti subspecies roqueforti. The four species Penicillium roqueforti subspecies roqueforti, P. commune, P. palitans and P. solitum made up 69.8% of the total number of isolates from the Norvegia cheese and 81.0% of the total number of isolates from the Jarlsberg cheese.