BACKGROUND: Several studies show that missing doses and an incorrect inhalation technique, are the most common pharmacological risks in patients with Chronic Obstructive Pulmonary Disease diagnosis. These are associated with an increase in Health-related costs, mainly due to an increase in the number of emergency visits, hospitalizations and switches of medication as a consequence of therapeutic failures. OBJECTIVES: to determinate the median cost per month of each patient stratified by type of pharmacological risks, after pharmacotherapeutic follow-up assessment. METHODS:  Type of study: analysis before and after. Patients diagnosed with COPD. Observation period: January 2012 to June 2014. (N: 108). risk-pharmacological: Incorrect inhalation technique and skip-doses. Outcome of interest: the average cost was calculated cost-month-patient before and after the education provided by the Pharmaceutical, stratified into two groups, those patients with risk-pharmacological and those who have not. RESULTS: The median cost per month was 165.3 [104.0-277.8] USD, a patient without pharmacological risks was 119.2 [88.9-201.4] and a patient with pharmacological risks was 186.7 [123.7-307.9] [p value= 0.033]. On the other hand, a patient with missing doses was 195.1 [131.6-297.6], in comparison with a patient with incorrect inhalation technique, that was 143.0 [96.3-169.0]. The cost before the Pharmacotherapeutic Follow-up implementation was 169.8 [110.8-253.8] and after that it was 150.7 [106.7-278.1], with an important decrease of 11,25% [p value= 0.517]. CONCLUSIONS: Having pharmacological risks was related with a higher median cost per patient. The median cost per patient was lower after giving Health-related education to patients by Pharmacotherapeutic Follow-up.