Freshly harvested cells of Penicillium crustosum Them VKM F-1746 were more capable of excreting roquefortine than transporting it. The ability to accumulate roquefortine was enhanced and the ability to excrete was decreased by starvation in Tris-Mops, pH 6, for 1-2 days, correlating with the loss of cell nitrogen. Excretion of roquefortine from the cells of P. crustosum was energy-independent. In contrast, transport into P. crustosum proceeded both in energy-dependent and -independent ways by saturation mechanisms. The optimal pH of the transport was 4.5 and that of the excretion about 6-7.