Objective. Measure and compare the price, availability, and affordability of insulin and metformin in public and private pharmacies in six regions of Peru. Methods. Cross-sectional study using the World Health Organization/Health Action International (WHO/HAI) revised methodology. Public and private pharmacies in six regions of Peru were surveyed. Data were collected on availability and prices for insulin (all types) and 850 mg metformin. Availability is expressed as percentages and prices are reported in medians. Affordability is defined as the number of days that a person must work at minimum wage to cover the cost of one month of treatment. Results. Availability in public pharmacies is 63.2% for regular insulin and 68.4% for NPH (isophane) insulin, but differences in availability were observed between levels of care and between regions. Private pharmacies have a greater variety of insulin, but availability is less than 11%. The median price of human insulin was three to four times higher in private pharmacies than in public pharmacies. In comparison, availability of metformin was 89.5% in public pharmacies and 77.7% in private ones. Affordability in public pharmacies for one month of treatment with human insulin or generic metformin is less than one day’s wages. Conclusions. The price for human insulin and generic metformin in public pharmacies is affordable. However, efforts are needed to improve their availability in the different regions and levels of care.