The free-living marine nematode Innocuonema tentabunda was collected from the mangrove sediment of a mud-flat at Chorao Island, Goa, India, and reared in the laboratory to investigate its life cycle at 27 plus or minus 2 degrees C. The nematodes were fed with cultured bacteria and diatoms. Copulation was observed one day after females and males were put together in cavity blocks. Eggs were clearly seen inside females 2 days after they were fertilized, when egg laying started, and a single female could lay 10-20 eggs. The egg diameter varied from 40 mew m (newly laid) to 57 mew m (before hatching). Eggs hatched 3 days after being laid. The first stage juvenile, after hatching, took about 20 days to reach the adult stage. The length of juveniles averaged 150 mew m when they first emerged from the egg and 505 mew m when they were 9 days old. The length of fully grown specimens varied between 700 and 900 mew m