Objective: To describe and compare the pattern of morbidity in a general practice casualty with primary care patients in emergency departments (EDs). Setting and subjects: Patients presenting to a general practice casualty and primary care patients in two EDs in Sydney, NSW. Results: The pattern of morbidity in the general practice casualty was similar to that among ambulatory patients in EDs. Conclusion: Opportunities may exist to substitute care between casualty services provided by GPs and those provided in EDs.