The induction of intracytoplasmic membranes was demonstrated to occur in Acinetobacter sp. when grown on hexadecane, heptadecane, and hexadec-1-ene. 2. Evidence for a physical relationship between the cytoplasmic hydrocarbon "pools" and the intracytoplasmic membranes is presented. 3. The specificity of cytoplasmic pooling of hydrocarbons and the induction of intracytoplasmic membranes was investigated in relationship to hydrocarbon oxidation. 4. These results suggests that both processes are required for the growth of Acinetobacter sp. on hydrocarbons.