Introduction. Bipolar Disorders cause high morbidity and mortality rates, particularly in young population. It causes elevated use of health resources and has a high economic cost for individuals and society. Objectives. To assess resource utilization in a cohort of patients with a First Manic Episode and perform a cost estimation of the First Manic Episode and the cost of the maintenance treatment until the onset of a new episode within a 52 week follow up period at Instituto Nacional de Psiquiatría “Ramón de La Fuente”. Methods: Data from BD patients in their First Manic Episode were prospectively collected. We considered only direct medical costs (hospitalization, drug treatment, laboratory tests and psychiatrist visit). Unitary costs were obtained from the Ministry of Health. Results are expressed in U.S. Dollars. Results: 52 BD patients were included. 98% of patients required inpatient treatment for the First Manic Episode with an average stay of 34.66 days. Total mean cost for treatment of the First Manic Episode was $6,877.39. Hospitalization represented 84.35% of the total costs in the acute episode. The one-year recurrence rate was 40.44% , during maintenance treatment 70.59% of patients took one or two-drug treatment, average psychiatrist visits was 8.21. Total mean costs for the maintenance treatment period for patient was $1,270.49. The 72.21% of total mean costs corresponds to drug treatment. Conclusion: First Manic Episode treatment demands high resource utilization in comparison with maintenance treatment, requiring therefore to focus in strategies to improve early diagnosis and therapeutic adherence to avoid latter costs.