Background: Globally, there is growing concern regarding workers’ illicit drug use and its implications for health and workplace safety. Young workers in male-dominated industries, such as construction, may be more susceptible to illicit drug use, risky drinking and its associated harms. Purpose/objectives: To investigate drug use and perceptions of risk among male construction workers, drawing comparisons between workers under 25 years with older age groups. Methods: Workers in Sydney, Australia (N = 511) completed a survey measuring past year illicit drug and alcohol use, psychological distress and perceptions of drug-related risks to health and safety. Prevalence in the total sample was compared with national estimates, and differences between younger and older survey respondents were examined using logistic regression models. Results: Survey respondents’ cocaine, meth/amphetamine and cannabis use was significantly higher than estimates of male employees nationally (OR = 6.60, 3.58, 1.61, respectively). Young workers ≤24 were more likely to frequently use illicit drugs, drink heavily, and report psychological distress than those aged 35+. Workers ≤24 were least likely to perceive that drug use posed high risks to health or safety when compared with 25-34 and 35+ age groups. Conclusions/importance: The findings highlight the high prevalence of illicit drug use amongst young construction workers, representing threats to workplace safety even if used outside work hours. Greater emphasis on potential adverse effects of alcohol and drug use and closer examination of contributory workplace factors are required. These findings have practical implications to inform occupational health and safety programs and interventions in high-risk workplaces.