Background: The modified Medical Research Council scale (mMRC) is a standardized measure of the effect of dyspnea on the activities of the daily life of patients suffering from Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to determine the differences in the quality of life, tolerance to effort and symptoms among patients with COPD with lower (mMRC 0-1) and greater symptoms (mMRC ≥2). Methods: Cross-sectional study that included patients admitted to a pulmonary rehabilitation program and who were classified into 2 groups: a group containing the less symptomatic patients and another group with the more symptomatic ones. We collected these patients’ sociodemographic, clinical, anthropometric, anxiety, depression and quality of life (SGRQ) data. Likewise, the subjects performed the 6-minute walk test (6MWT). Finally, we measured the multidimensional BODE index score. Results: 130 subjects were included, 35 presenting an mMRC of 0 to1 and 95 having an mMRC ≥ 2, with an age of 70.87 ± 9.45 years old. The 6MWT distance, the VO2e, the total score of SGRQ, and its domains of activities and impact showed significant differences between the groups (p <0.05). Significant correlations were found in the group presenting an mMRC of 0-1 between the mMRC and the FEV1 (p = 0.028), and in the group with an mMRC ≥2 for the FVC (p = 0.031), the 6MWT distance (p = 0.000), the VO2e (p = 0.010) and the BODE index (p = 0.000). Conclusion: Patients with an mMRC of 0 to1 had better results in the 6MWT, the VO2e and the SGRQ in comparison with the most symptomatic ones.