OBJECTIVES: To characterize the supply, demand and the gap of medical specialists in facilities of the Ministry of Health of Peru (MINSA) at the national, regional and specialty type levels. MATERIALS AND METHODS: Observational, descriptive study through which we calculated the supply of medical specialists using secondary sources of MINSA. The analysis of the demand for medical specialists was based on two methodologies: the need for specialists according to the guidelines of classification of the health facilities and according to the epidemiological and demographic profile. The arithmetic difference between the estimated demand and the supply was the procedure used to calculate the gap of medical specialists. RESULTS: The Ministry of Health has a total supply at the national level of 6,074 medical specialists of which 61.5% belong to the clinical specialties, 33.2% to the surgical specialties, 4.9% specialities related to aid to diagnosis and treatment and 0.4% to public health specialties. According to the categorization guideline there is a total demand of 11,176 medical specialists and according to the epidemiological and demographic profile of 11,738. The national estimated gaps found are similar in both methods, although they differ widely across regions and by type of specialty. At the regional level, the gaps are greater in Loreto, Piura, Puno and Madre de Dios when estimating the defficit in relation to the supply. Regarding the speciality, the gap is greater in the four basic specialties: gynecology and obstetrics, pediatrics, internal medicine and general surgery. CONCLUSIONS: There is a waid gap between supply and demand of medical specialists at the national and regional levels, as a whole representing approximately 45% of the current offer, regardless of the estimation method.