The synthesis of bioactive lipids in three species of lower mycelial fungi of the genus Pilaira, the family Pilobolaceae, has been studied. The pigmentation of these fungi was found to be determined by the presence of beta-carotene in amounts of 14.8 (P. moreaui), 115.7 (P. caucasica), and 312.9 (P. anomala) microg/g. The fatty acid profiles of the fungi, which are distinguished by the presence of up to 50% essential fatty acids, is typical of zygomycetes of the order Mucorales. The fungi grown in submerged cultures showed a correlation of the unsaturation indices of their fatty acids and the contents of beta-carotene.