Autistic individuals may be at risk of premature mortality, and physical health comorbidity increases this risk; however, most studies fail to include older autistic adults or consider lifestyle-related factors that affect health. We developed an anonymous, online physical health survey. The final sample included n = 2368 individuals (mean age = 41.42), and of these, n = 1156 were autistic individuals (mean age = 40.98). We utilized three sex-stratified statistical models to determine the prevalence of cancer, cardiovascular conditions, respiratory conditions, and diabetes. All three models indicate that autistic females are more likely to have cardiovascular conditions, respiratory conditions, asthma, low blood pressure, arrhythmias, and prediabetes than non-autistic females, and autistic males are more likely to have arrhythmias than non-autistic males; these results suggest that autistic individuals carry increased risks for these conditions when compared to the general population, even after controlling for age, ethnicity, education level, body mass index, smoking, and alcohol use. Further, these risks may differ depending on biological sex for autistic individuals. Autistic adults, and particularly autistic females, have greater and wider-ranging risks than previously thought, even after controlling for demographic and lifestyle-related factors. Although this is a large sample of autistic adults across the lifespan, future research should employ larger, population-based samples to confirm these findings.