In a stylised model involving a developing country (called South) and a foreign patent holder, we analyse whether and how the incidence and social value of compulsory licensing (CL) depends upon the South's patent protection policy. If South is free to deny patent protection, CL fails to arise in equilibrium and the option to use it makes both parties worse off. If South is obliged to offer patent protection, CL can occur and even yield a Pareto improvement. The ability to control price increases the South's incentive for patent protection as well as the likelihood of CL.