Evidence suggests increased mortality rates among autistic individuals. However, risks of mortality, including natural-cause, suicide, and accident mortalities, among autistic individuals remain unclear. Among the entire Taiwanese population (N = 29,253,529), between 2003 and 2017, 45,398 autistic individuals were identified and 1:4 matched to 181,592 non-autistic individuals based on birth year and sex. All-cause mortality, including natural-cause, accident, and suicide mortalities, was assessed from 2003 to 2017 between the two cohorts. Cox regression models were used to investigate the mortality risk between autistic and non-autistic individuals. Autistic individuals had increased likelihoods (hazard ratio, 95% confidence interval) of all-cause mortality (3.43, 3.00-3.92), natural-cause mortality (4.73, 3.99-5.60), and suicide mortality (3.67, 2.37-5.68) compared with non-autistic individuals. In particular, autistic males were more likely to die by suicide (hazard ratio: 3.81, 95% confidence interval: 2.37-6.13), and autistic females were more likely to die of accident (hazard ratio: 5.07, 95% confidence interval: 2.54-10.13) compared with non-autistic individuals. Appropriate and effective medical and mental health care is recommended for autistic individuals.