Data were collected by the local nurse on each of the 36 drownings in domestic swimming pools of under 5 year olds that occurred between 1 September 1982 and 31 December 1986. The likely effect of New Zealand's 1987, Fencing of Swimming Pools Act in preventing these drowings, had it been in effect, is considered. It is concluded that at least 29 (80%) of the 36 drownings would have been prevented. Examination of the circumstances of the drownings leads to the conclusion that certain alternatives to the fencing law that have been proposed, such as teaching water skills to infants, fencing property boundaries, and use of pool covers, are unlikely to have been as effective.