In Mexico, six of every twenty Mexicans suffer psychiatric disorders at some time in their lives. This disease ranks fifth in the country. The objective was to determine and compare the cost-effectiveness of two models for hospital care (partial and traditional) at a psychiatric hospital of Instituto Mexicano del Seguro Social (IMSS). a multicenter study with a prospective cohort of 374 patients was performed. We made a cost-effectiveness analysis from an institutional viewpoint with a six-month follow-up. Direct medical costs were analyzed, with quality of life gains as outcome measurement. A decision tree and a probabilistic sensitivity analysis were used. patient care in the partial model had a cost 50 % lower than the traditional one, with similar results in quality of life. The cost per successful unit in partial hospitalization was 3359 Mexican pesos while in the traditional it increased to 5470 Mexican pesos. treating patients in the partial hospitalization model is a cost-effective alternative compared with the traditional model. Therefore, the IMSS should promote the infrastructure that delivers the psychiatric services to the patient attending to who requires it.