This study investigated the effect of moral hazard on the reporting of health problems in the public sector. Moral hazard was demonstrated by a comparison between public and private employees of self-reporting hard-to-diagnose health problems. Data for the analysis were taken from a sample of over 120,000 workers from the U.K. 2010 Labour Force Survey. Results revealed that, against the posited hypotheses, the opportunistic behavior was equal between public employees and permanent workers from the private sector. However, differences were found in reporting behavior between public employees and personnel with contractual positions where the risk of unemployment was higher.