Studies of the hydrocarbon utilizing yeasts, Candida maltosa and C. lipolytica, have shown that both were capable of reducing recoverable amounts of branched chain and aromatic hydrocarbons in a mixture of naphthalene, tetradecane, hexadecane, pristane (tetra-methylpentadecane). Cells of C. lipolytica grown on either glucose or tetradecane were capable of binding (rendering unextractable) nearly 50% of the hydrocarbon mixture within 3 hours. In contrast cells of C. maltosa bound hydrocarbons only after growth on a hydrocarbon medium. Uptake of selected paraffinic hydrocarbon was not altered by the presence of naphthalene. Pristane uptake was concentration dependent for C. maltosa but not for C. lipolytica. Uptake, transport, and metabolism of hydrocarbons in C. maltosa and C. lipolytica differ.