Suicides are prone to misclassification during death-ascertainment procedures. This problem has generated frequent criticism of the validity of suicide mortality statistics. The study aim was to employ an external measure of the validity of cause-of-death statistics, national autopsy rates, to examine potential misclassification of suicide across 35 countries. Data for the time period 1979–2007, were employed to analyze the association between suicide rates and autopsy rates and death rates of undetermined and ill-defined causes, respectively. Autopsy rates among nations were associated with suicide rates. These respective associations were robust with adjustment for unemployment, degree of urbanization, and the rate of undetermined or ill-defined deaths. Associations strengthened when analyses were confined to 19 EU member countries. Based on these results, we conclude that autopsy rates may impact the validity of suicide mortality statistics. Therefore, caution should be exercised in comparing international suicide rates and evaluating interventions that target suicide rate reduction.