Using a simple theoretical model we conjecture that dual practice may increase the number of patients seen but reduce hours spent at public facilities, if public physicians lack motivation and/or if their opportunity costs are very large. Using data from Indonesia, we then test these theoretical conjectures. Our identification strategy relies on a 1997 legislation necessitating health professionals to apply for license for private practice only after three years of graduation. Results using a difference-in-difference regression discontinuity design provides support to our conjectures, identifying the role of weak work discipline, lack of motivation and opportunity costs of public service provision.