Examined annual variations in the methods used for suicide in the United States in recent years (1962-1975) by sex and ethnic groups (white males, white females, nonwhite males, nonwhite females). Virtually all of the increase in United States suicide rates between 1962 and 1975 can be attributed to the increase in suicides by firearms. The increase in suicides by firearms, which occurred in all sex-ethnic groups, accompanied marked increases in the availability of firearms, which is a preferred, socioculturally accepted method of suicide in the United States. These results present a mirror image of the reductions in suicide rates in Great Britain and Vienna when the availability of the most preferred method of suicide in those locales (toxic domestic gas) was reduced. The data from this and other studies suggest that the physical availability of the more culturally accepted methods of suicide is a major determinant of suicide rates and that suicides may be prevented by decreasing the availability of the most common methods of suicide to suicidal individuals.