This paper reports on an empirically-based study of the way in which the Magistrates' Courts in Victoria, Australia, construct occupational health and safety (OHS) issues when hearing prosecutions for offences under OHS legislation. Since the Factory and Shops Act 1885, the Victorian parliament has responded to this problem by enacting statutory standards regulating workplace hazards. These statutory standards have been enforced by a state inspectorate, which has used a variety of enforcement strategies ranging from informal methods, such as advice, persuasion, education and warnings, to formal invocation of the criminal law before the Magistrates' Courts (and since 1985, the County Court), as a last resort. Since the 1830s in Britain, and the 1880s in Australia, the Magistrates' Courts have played a major part in the process of examining, constructing and adjudicating all aspects of the OHS offences, particularly the determination of whether an offence has in fact been committed, and the level of punishment to be exacted. Despite the importance of prosecution in an occupational health and safety (OHS) regulatory regime, and the disquiet at the clear inadequacies of prosecution of those contravening OHS statutes, there has been little research into the way in which the courts hear OHS prosecutions. This study aims to fill this gap, and to build on an earlier study of OHS prosecutions in Victoria from 1885-1979. The paper reports on an empirically-based examination of the manner in which the Magistrates' Courts in Victoria, Australia, construct OHS issues when hearing prosecutions for offences under the OHS legislation (the Industrial Safety, Health and Welfare Act 1981 (Vic) (ISHWA) and the Occupational Health and Safety Act 1985 (Vic) (OSHA)). The study covered the period 1983-1999. The data was drawn from observations of prosecutions, interviews with inspectors, prosecutors and magistrates, participant observation of inspectors and prosecutors, and the statistical analysis of case reports.