Consultation with another physician is considered to be an important safeguard of the practice of euthanasia and physician-assisted suicide. The objective is to describe the frequency and characteristics of consultation in cases of euthanasia or physician-assisted suicide (EAS) in the Netherlands. Data from two cross-sectional descriptive nationwide surveys, carried out in 1995, were used. Questionnaires were mailed to physicians attending 6060 deaths, identified from death certificates, and a stratified sample of 405 physicians were interviewed. In 1990, a cross-sectional descriptive postal survey of a random sample of 1042 general practitioners took place. Consultation took place in 63% of cases of EAS in the Netherlands, in 99% of the cases reported to the public prosecutor and in approximately 37% of unreported cases. In almost half of the unreported cases the decision had been discussed less formally with at least one colleague. In 1990, 7% of general practitioners met all 8 criteria for good consultation; this increased to 64% in 1995. Of the respondents, 26% had at some time advised against performing euthanasia or assisted suicide when acting as a consultant. This study shows that approximately two thirds of all cases of EAS are safeguarded by consultation. Although in the majority of these cases the consultation is of good quality, there is certainly still room for improvement. The quality of consultation could be improved, for instance, by appointing independent and specifically trained consultants.