This study compares the Los Angeles Suicide Prevention Center program with that of the Samaritan Centre in the London area. The author interviewed senior personnel and reviewed the training program for volunteers in both centres. He also monitored calls but was prohibited from listening in on the callers' conversation in the Samaritan program due to their strict policy of confidentiality and anonymity. The purpose of the study was to learn the nature of the calls with special emphasis on suicide risk and degree of crisis; to assess the functioning of the volunteers in detail and compare it with professionals; to assess the usefulness of the programs in lowering the suicide rate and in other functions, particularly dealing with crises and case finding. It was found that the involvement with callers is very similar in both centres; that only a small percentage of callers had a significant suicidal drive; that many of the callers were in crisis and a useful service was provided for them; that the volunteers coped extremely well with disturbed callers even though their responses were often different from professionals. There is no evidence that these and similar, primarily telephone, services lower the suicide rate; they seem to be more effective as crisis centres than as suicide prevention centres.