The free living nematode Panagrellus redivivus has been maintained in serial axenic culture for 6 months. P. redivivus was freed from bacteria in a semi-automatic device using antimicrobial agents. Cultures have been established and maintained monoxenically on nutrient agar slants with Escherichia coli, and axenically in a liquid medium containing soya peptone, yeast extract and heated liver extract. Cultures of P. redivivus have been maintained by serial subcultures in a chemically defined medium supplemented with purified protein growth factor (40 μg/ml) under the defined conditions designed for nutritional studies with the protandrous hermaphrodite, Caenorhabditis briggsae (Rhabditidae) . P. redivivus appears to be obligately dioecious. Reproduction has not been impaired by cultivation in liquid media. In marked contrast to C. briggsae, P. redivivus is able to survive 4° C for 3 months.