BACKGROUND The suicide risk of patients with cancer is higher than the general population. Our research aimed to explore the Surveillance, Epidemiology, and End Results (SEER) database to define incidence and quest risk factors for death of suicide in patients with Kaposi's sarcoma (KS) in the United States (US). MATERIAL AND METHODS We screened KS patients without human immunodeficiency virus status in the SEER database from 1980 to 2016, calculated the standardized mortality ratios of them by comparing the rates with those of the US general population from 1980 to 2016, and identified relevant suicide risk factors by univariable and multivariable logistic regression analyses. RESULTS The suicide rates of KS patients and US general population were 115.31 (110 suicides among 21 405 patients) and 15.1 per 100 000 person-years, respectively, thus the standardized mortality ratio was 7.64 (95% confidence interval [CI], 6.28-9.21). The multivariate analysis showed that black race (versus white race, hazard ratio [HR]: 0.43, 95% CI: 0.21-0.89, P=0.022), advanced age at diagnosis (≥55 years versus 18-44 years, HR: 0.31, 95% CI: 0.14-0.66, P=0.002), and chemotherapy (versus no chemotherapy, HR: 0.60, 95% CI: 0.37-0.96, P=0.032) were protective factors for suicide among KS patients. CONCLUSIONS Clinicians and caregivers can apply our findings to identify KS patients with high suicide risk characteristics (white race, age of 18-44 years, non-chemotherapy) and exert timely interventions during patient diagnosis, treatment, and follow-up to reduce the suicide rate in this population.