INTRODUCTION AND OBJECTIVE: Dyspnoea is a major symptom in COPD patients, but the determinants that could be associated with a higher dyspnoea mMRC score in COPD patients remain unclear. Our research aimed to study the determinants of dyspnoea at the threshold of 1, 2, 3 and 4 mMRC. PATIENTS AND METHODS: Diagnosis of COPD was made using spirometry with post-bronchodilator FEV(1)FVC<70%. An online questionnaire has been employed by pulmonologists to recruit COPD patients. The following variables were collected: age, gender, BMI, FEV(1), RV, IC, TLC, FRC, mMRC, frequency of exacerbations and comorbidities. The LASSO was used to select the variables associated with the mMRC dyspnoea scale in a subgroup (who had no missing IC, RV and FRC values) of 421 COPD patients defined by the previously mentioned variables. RESULTS: One thousand nine hundred and sevety-three patients (65.3% males, average age=66±10, 38% current smokers) were included. Dyspnoea was correlated with a low FEV(1) and with the number of exacerbations in the past 12 months. Multivariate analysis showed that the determinants of dyspnoea(mMRC?2) are: FEV(1): OR=3.71[2.86-4.82]; anxiety: OR=2.52[1.82-3.47]; cough: OR=1.94[1.57-2.40]; bronchiectasis: OR=1.84[1.03-3.29]; age: OR=1.80[1.45-2.24]; hyperinflation (RV/TLC): OR=1.68[1.34-2.11]; ischemic cardiopathy: OR=1.63[1.22-2.18]; hypertension: OR=1.52[1.21-1.91]; exacerbations (?2): OR=1.41[1.10-1.81]; women: OR=1.39[1.10-1.74] and overweight: OR=1.33[1.06-1.67]. The subgroup analysis showed that: FEV(1): OR=3.47[1.96-6.12]; exacerbations (?2) OR=2.31[1.33-4.17] and hyperinflation (IC/TLC) OR=0.57[0.35-0.85] were associated with higher dyspnoea (mMRC?2). CONCLUSION: Our results showed that dyspnoea is related to the severity of airflow limitation, gender, exacerbations, comorbidities and hyperinflation.< Réduire