Sphingolipids were found to dominate in the glycolipids from the cell envelope of baker's yeast. A relatively large quantity of ceramides was detected. Among the several complex phosphosphingolipids described, ceramide-(P-inositol)2-mannose was the main component. About 55% of long-chain bases in sphingolipids consisted of C18-phytosphingosine (4D-hydroxysphinganine). Other bases, found in decreasing concentrations, were C20-phytosphingosine, C20-dehydrophytosphingosine, C18-dihydrosphingosine (sphinganine) and C19-dihydrosphingosine. The presence of sterol glycosides, sulpholipids, cerebrosides and acylglucoses was demonstrated.