The use of rubber dam for endodontic treatment in New Zealand was analysed by a national survey of general dental practitioners. The response rate was 79 percent. Rubber dam was used routinely by 57 percent, its use increasing among practitioners graduating since 1969. A greater percentage of practitioners with less than 10 years experience used rubber dam than did more experienced practitioners. Use of rubber dam was associated with sodium hypochlorite and EDTA as canal irrigants. Reamers were the favoured hand instrument of non-users of rubber dam. No significant differences were found in the canal obturation techniques of users and non-users, but rubber dam users used the long-cone paralleling method of radiography significantly more than non-users. Practitioners in solo practice used rubber dam significantly less than those in group practice. Rubber dam users attended significantly more refresher courses in endodontics than non-users.