This book outlines the use of the casemix system as a provider payment tool in the health system with special focus on cost of pharmacy services of in-patient care. Casemix system, which is traditionally called Diagnosis Related Groups or DRG in more advanced economies, is now being implemented in many developing countries that plan to or have embarked on social health insurance programs as a source of the health funding. Extensive research has been carried out by the authors involving 13,673 patients that were prescribed with 111,794 items of drugs and admitted to one of the premier teaching hospital in Malaysia. Data from this research was vigorously analysed to impute the pharmacy service weights of all relevant casemix groups. This book provides the best reference for pharmacy service weights that can be used as a guide for effective implementation of the casemix system in any country in the world that plans to use the system.