Context Suicides are prone to misclassification during death ascertainment procedures. This problem has generated frequent criticism of the validity of suicide mortality statistics. Objective To employ an external measure of the validity of cause-of-death statistics (ie, national autopsy rates) and to examine potential misclassification of suicide across countries from Europe to Central and Northern Asia. Design Cross-national analysis. Setting Thirty-five countries. Participants Aggregated mortality data. Main Outcome Measures Data from 35 countries during the period from 1979 to 2007 were used to analyze the association of suicide rates with autopsy rates and death rates of undetermined and ill-defined causes, respectively. Analyses were cross-sectional and longitudinal. Results Cross-sectionally, a 1% difference in autopsy rates among nations was associated with a suicide rate difference of 0.49 per 100 000 population. Longitudinally, a 1% decrease in the autopsy rate aligned with a decrease of 0.42 per 100 000 population in the suicide rate. These cross-sectional and longitudinal associations were robust after adjustment for unemployment, degree of urbanization, and prevalence of undetermined or ill-defined deaths. Associations strengthened when analyses were confined to 19 European Union member countries. Conclusion Autopsy rates may spatially and temporally affect the validity of suicide mortality statistics. Caution should be exercised in comparing international suicide rates and evaluating interventions that target suicide rate reduction.