OBJECTIVES: determine the association between the improvement of medication non-adherence and the evolution of the dyspnea degree. METHODS: case-control study in patients diagnosed with COPD GOLD-D. Recruitment period: august 2015 and december 2017 (n: 70).Observation time: 18 months. Cases: patients who do not improve their initial dyspnea degree (n: 35).Univariate analysis: absolute and relative frequencies, summary measures and normality tests were used. Bivariate analysis: contingency tables and Chi-square tests, t-student (Mann Whitney U), ANOVA (H- Kruskal Wallis), mcnemar or wilcoxon. The statistical force measure used was the OR (Crude and adjusted). Multivariate analysis: Binary multiple logistic regression for explanatory purposes. RESULTS: the analyzed population was characterized by being women with advanced age, with low socioeconomic and education level, use oxygen, high exposure to wood smoke and cigarette.More than 50% of the population that began with a classification of dyspnea degree 4 and more than 46% of those who began in degree 3, improved their classification to less severe degrees.The dyspnea degree improvement between patients who improved their non-adherence and those who do not improved was 26%. Patients who improved their medication adherence were 5 times more probabilities to improve their dyspnea degree, whene it is adjusted fo sex, work status, BMI, oxygen use, smoke and dyspnea baseline degree (adjusted OR 5.19 [1.21 - 22.2]). CONCLUSIONS: improve the medication non-adherence, is associated with a better of the dyspnea degree evolution.