Background: Many patients visit the accident and emergency department (AED) on their own initiative, although their medical problem can be adequately treated by a general practitioner (GP). Objective: To evaluate the cost-effectiveness of addition of a GP to the AED (new care method) in comparison with usual care (usual care method). Methods: This study followed a before/after design. Patients attending the AED without a referral on weekdays from 10:00 to 17:00 were invited to participate. Main outcome measures were process time, patient satisfaction and number of correct diagnoses. Costs were measured from a societal perspective. Bootstrapping was used to estimate uncertainty around differences in costs and incremental cost-effectiveness ratios. Cost-effectiveness planes and acceptability curves were presented. Results: Addition of a GP to the AED resulted in significantly lower process time, significantly higher patient satisfaction and no statistically significant difference in the number of correct diagnoses. Total costs per patient were €217 in the new care period and €288 in the usual care period (mean difference -€71, 95% CI -121 to -23). The cost-effectiveness analysis showed that the new care method was dominant (more effective, less expensive) in comparison with the usual care method for process time and patient satisfaction. The new care method was considered cost-effective in comparison with the usual care method for ceiling ratios between €0 and €1363 for the number of correct diagnoses. Conclusion: The new care method consisting of addition of a GP to the AED is cost-effective in comparison with usual care for all outcome parameters measured.