The carbohydrate and lipid components of mycelium and conidia of Fonsecaea pedrosoi (Brumpt) were analysed by paper, thin-layer and gas-chromatography, mass spectrometry and ultraviolet spectroscopy. Glucose, mannose, galactofuranose, rhamnose and glucosamine were polysaccharide components identified in F. pedrosoi. Significant changes in the carbohydrate pattern occurred during the conversion of mycelium into conidia. Rhamnose was predominant in conidia whereas galactose was prominent in mycelium. Palmitic, stearic, oleic, linoleic, and arachidonic acids were the fatty acids identified in the total lipid fraction. Palmitic and oleic acids were major fatty acids. Marked alterations in the fatty acid constituents were observed between the cell types of F. pedrosoi. Arachidonic acid was detected only in conidia and linoleic acid was preferentially identified in mycelium. Differences in the sterol composition was also associated with morphogenesis in F. pedrosoi. Two main sterols, ergosterol and another less polar sterol, not fully characterized, were found in mycelium whereas in conidia only the latter sterol was present.