Opioid abuse is a leading cause of drug-related morbidity and mortality worldwide. It has been suggested that the age of opiate users in Australia is rising. To evaluate this further in a local population, toxicology and pathology case files from Forensic Science SA, Adelaide, South Australia, were examined for all cases with lethal opioid levels from 2000 to 2019 (n = 499; M:F 2.3:1; age range 18-91 years, median age 42 years). The median age of opiate deaths increased significantly by approximately 16 years (p = 0.007, R2 = 0.34) with a significant increase in total deaths in the 45-54 years and 55-64 years age groups (p = 0.009, R2 = 0.32) (p = < 0.001, R2 = 0.54). Deaths due to heroin overdose showed the lowest median age (39 years, n = 184), with deaths from tramadol toxicity having the highest (50.5 years, n = 32). Recent changes in the demographic profile of opioid users in cases of lethal overdose involve an aging population. Forensic and clinical practitioners should be aware of significant opioid abuse in certain individuals at older ages as this raises the possibility that this may exacerbate the effects of age-related chronic diseases in this group and/or contribute to fatalities.