OBJECTIVES: Informal reports have suggested that work as a waste collector entails exposures that cause gastrointestinal symptoms--such as nausea and diarrhoea. This study explores this hypothesis by correlating data on the type of waste collected, the persons' job function, the equipment used, and the times of the week and the year of reported nausea and diarrhoea. METHODS: 1747 male waste collectors and a control group for comparison of 1111 male municipality workers answered a questionnaire on work environment, work related exposure, and health status. RESULTS: In a multivariate analysis collection of organic and residual waste (prevalence proportion ratio (PPR) 1.45) and mixed household waste (PPR 1.43) were associated with reported nausea and so was the job loader (PPR 1.51). More symptoms were reported in the summer. Multivariate analysis of diarrhoea showed that the job front runner was associated with reported diarrhoea (PPR 1.22) and so was the job loader (PPR 1.26). More symptoms occurred in the summer. The workers stated that the gastrointestinal symptoms were related to the smell of rotten waste. This may support the hypothesis that microbial compounds were the causal agents. CONCLUSION: The gastrointestinal symptoms were associated with the job of waste collector and moreover the symptoms predominantly occurred in the summer.