Background <p>Accurate information on where suicides occur; especially in domestic settings, is essential for designing prevention programs. In practice, place of death from death certificates is used as a proxy, though its accuracy is unclear. This study assessed the validity of using death certificate data to determine place of suicide, using linked records from the Suicide Surveillance System in Taiwan.</p> Methods <p>We linked mortality data with the Suicide Surveillance System in Kaohsiung City, Taiwan, from 2021 to 2023. Using the place of suicide recorded in the surveillance system as the reference standard, we estimated the proportion of suicide deaths in each place-of-death category (home, hospital, and other) that actually occurred at home.</p> Results <p>Among 1465 suicide deaths, 965 were successfully linked to the Suicide Surveillance System. The positive predictive value for death at home was high: 99.3% for hanging, 97.8% for charcoal burning, and 100.0% for other poisoning. Many suicides recorded as hospital deaths actually occurred at home, including 79.3% of hanging, 66.7% of charcoal burning, 85.5% of other poisoning, and 71.6% of jumping cases. After adjustment, the estimated proportion of suicides occurring at home was 80.4% for hanging, 68.2% for charcoal burning, 77.9% for other poisoning, 75.0% for jumping from a height, and 60.2% for other methods.</p> Conclusions <p>Using death certificates alone underestimates suicides at home. Improved data integration is needed to support more accurate surveillance and better-targeted suicide prevention efforts.</p>