OBJECTIVES: Reimbursement processes have been implemented to inform which therapies should be funded in light of scarce healthcare resources. However, the applicability of standard processes to drugs for rare diseases is heavily debated. As a result of the small patient populations affected by rare diseases, coupled with a limited understanding of the natural history of these conditions and the high cost of these treatments, it is argued that drugs for rare diseases may not meet the evidentiary standards routinely applied when making resource allocation decisions. This study identified current reimbursement processes for prescription pharmaceuticals both within Canada and internationally, with the objective of assessing how drugs for rare diseases are considered within existing processes.   METHODS: Using the G20 countries as a sampling frame, a review of published and grey literature was conducted to identify the reimbursement processes used in 28 countries, and in Canadian provinces/territories. A search for peer-reviewed publications was conducted using Medline, Scopus, CINHAL, EconLit and PsychInfo. The grey literature search included websites of health technology assessment agencies and government agencies.  RESULTS: Drugs for rare diseases are considering uniquely for reimbursement within three Canadian provinces and seven countries. Reimbursement frameworks focused specifically on the reimbursement of drugs for rare diseases are limited.  In some jurisdictions, drugs for rare diseases are considered uniquely within the established decision-making process for drugs. Varying decision criteria are applied within the identified processes for the reimbursement of drugs for rare diseases. CONCLUSIONS: This review identifies approaches for making resource allocation decisions for drugs; explicitly considering funding decisions related to drugs for rare diseases. An understanding of these frameworks and the decision criteria applied when making resource allocation decisions may help inform the development of more standardized approaches for the reimbursement of drugs for rare diseases.