Based on the new social security system in Colombia (1993), which establishes equity and mandatory care as the basis for public health care provision, the authors analyze whether the formulation and implementation of pharmaceutical policy promote accessibility, availability, and rational use of medicines, thereby contributing to equity in health. Two approaches were used: a macro approach centered on the legal framework and various actors in the reform process and a micro approach related to the processes and results in the drug supply system. The authors studied the legal instruments backing the country's pharmaceutical policy and evaluated their application, using indicators and a specific disease (diabetes mellitus) as a marker. Although there is a legal framework providing the people's right to access health care services and essential medicines, the country lacks a comprehensive pharmaceuticals policy. Most of the institutions experience problems in distributing the medicines listed under the Mandatory Health Plan, a low percentage of medicines is dispensed at zero cost, and a major portion of patients purchase medicines through associations of diabetics or rely on alternative medicine. The study unveiled several obstacles to equity in health care coverage and access to essential medicines.