Epidemiological data on suicide & attempted suicide in Mannheim was discussed in this presentation. Ecological data for a 13-year period, 1966-1978, was analyzed. The strength & direction of correlations between attempted suicide rates & ecological properties of social disintegration varied with the level of the ecological unit. When streets & small neighbourhoods were studied, a high concentration of attempted suicide was found. Theories which attempt to explain suicidal behaviour in terms of psychological infection & transmission were discussed.