Background Neuropsichiatric diseases constitute the first cause of burden of disease in Peru. Objective The aim of this study was to describe 12 month mental health services utilization, of the 18 to 65 years old urban population in Peru. Method As part of the World Mental Health Survey Initiative (WMHSI), this research used a multistage, clustered-area probability sample of 3930 18-65 years old household residents in Lima, Arequipa, Huancayo, Iquitos and Tacna between July 2004 and December of 2005. The Instrument used was the Composite International Diagnostic Interview (CIDI) that produces DSM-IV/ICD-9 diagnoses by means of computerized algorithms. Results In the last 12 months, only one of every 5 people who had a mental disorder during this period received any treatment. The average number of treatment visits per year was only three. 9.7[%] of those with any mental disorder received appropriate treatment. People with low education had less access to minimally adequate treatment (OR=0.1, 95[%] CI=0.0, 0.5). The group with substance use disorders had lower access to treatment in the last 12 months (12.7[%]). Discussion and conclusion Peru presents a wide gap in mental health treatment. Mental Health treatment gap in Peru emphasizes the need to direct resources towards screening and treatment of mental disorders.