This prospective observational study examined the outcomes of 200 consecutive admissions to an adult tertiary level Intensive Care Unit (ICU). Eligible and consenting participants were also involved in a sub-study that examined health status at four measurement points from pre-illness to 6 months post-discharge. Of the 189 individual patients admitted, 23% died in ICU and 57% were discharged home. The health status sub-study enrolled 34 participants (39% of eligible patients) who were representative of the ICU population for demographic and clinical variables. Surviving participants returned to a similar, though not identical state of health at 6 months post-discharge, when compared to their pre-ICU health-state using the 15D and SF-36 instruments. Health status at ICU discharge was significantly impaired when compared to other measurement points, particularly for mobility, breathing, eating, usual activities and vitality. A number of methodological challenges were evident, particularly for the health status sub-study, including prospective subject recruitment and retention, losses to follow-up and instrument responsiveness. Despite the limitations noted, the study provided useful findings and recommendations for the continued development of methods to examine the health status of critically ill patients.