This paper reviews the advantages and disadvantages of medical quality assurance methods commonly used in hospitals. A computer-based literature search up to April 1993 was done using the terms quality assurance, quality control, audit, utilization review, accreditation, occurrence screening and total quality management. In addition, a manual search was undertaken of references of papers obtained by the computer search and of the contents of the following journals: Quality Review Bulletin, Australian Clinical Review and the British Medical Journal. An assessment of the advantages and disadvantages of 15 quality assurance methods used in hospitals was made. Many quality assurance methods used in hospitals have significant disadvantages. A systematic method that provides meaningful and useful information to clinicians and improves patient care is urgently required. New methods such as occurrence screening and total quality management are slowly emerging and have much potential.