OBJECTIVES: The payer’s perspective is considered after a drug has been granted market access and launched. This is often too late as payers may not want to reimburse expensive drugs, especially if the current gold standard is cost effective compared to alternatives. This is mostly encountered if the drug was, during the clinical trials, compared to sub-standard comparators. This research aims to establish whether there are interventions to consider during a drug development cycle, and how, by using Key Intervention Points, a drug can be successful in the market. The first in a series of questions aims to define what exactly market access is. METHODS: A literature review was conducted on Ovid MEDLINE to establish a whether a clear and internationally validated definition of market access has been proposed. Included were articles and/or reviews concerning market access of pharmaceuticals for human use published from January 1999 to present day. RESULTS: Market access can be thought of as either gaining regulatory approval from bodies such as Food and Drug Administration or European Medicines Agency to make a drug available to patients, or as developing a drug that achieves blockbuster status through successful reimbursement, either through a high number of sales, or a higher-than-competitor premium price. Regulatory approval and reimbursement are often thought of as being inherently different, yet both share the central principle of balancing the benefits and harms in deciding availability of drugs. The main difference between regulatory approval and reimbursement is the scope of benefits and harm, and the population they consider. CONCLUSIONS: Market access is difficult to define, with different opinions and perspectives. There currently lacks a clear, internationally validated method of defining exactly what it market access entails, and what it means to have successfully achieved it. There is a need to definitively define this important concept.