Fission was studied in a population of Holothuria leucospilota at Darwin harbour. Fission resulted in smaller size anterior portions (A to P ca. 34.81%). A greater number of posterior individuals (P and Pa) may be assumed to mean a greater survival capacity than with anterior individuals (A and Ap). Monthly observations from September 1998 to September 1999 revealed that fission occurred throughout the year at an estimated rate of up to 28% at East Point and 8% at Nightcliff. At East Point, maximum fission occurred in April and coincided with a period of sexual reproduction, when annual precipitation was at a maximum and the reefs were exposed for less than 4 hrs day-1. This study suggests that H. leucospilota may use fission to maintain population level when sexual recruitment fails.