Arthrobacter aurescens TC1, Arthrobacter chlorophenolicus A6, Arthrobacter crystallopoietes, and Arthrobacter oxydans produce long-chain monoalkenes, predominantly cis-3,25-dimethyl-13-heptacosene. Four other Arthrobacter strains did not form alkenes. The level of cis-3,25-dimethyl-13-heptacosene in Arthrobacter chlorophenolicus A6 remained proportional to cell mass during growth. cis-3,25-Dimethyl-13-heptacosene did not support growth of A. chlorophenolicus A6.