Résumé : Objective: To investigate the clinical patterns and disease evolution of laryngopharyngeal reflux (LPR) patients. Methods: Patients with LPR diagnosed by hypopharyngeal-esophageal impedance-pH monitoring were prospectively followed in three medical centers. Symptoms and findings were assessed with reflux symptom score (RSS) and reflux sign assessment (RSA). Patients were treated with 3-to 9-month diet and combination of proton pump inhibitors, alginate or magaldrate. Patients were followed for 3 years to determine the clinical evolution of symptoms over time. LPR that did not recur was defined as acute. Recurrent LPR consisted of reflux with one or several recurrences yearly despite successful treatment. Chronic LPR was reflux with a chronic course of symptoms. Predictive indicators of clinical evolution were investigated. Results: One hundred forty patients and 82 healthy individuals completed the evaluations. Among patients, 41 (29.3%), 57 (40.7%), and 42 (30.0%) had acute, recurrent, or chronic LPR respectively. Baseline quality of life-RSS (QoL-RSS) and RSS total scores were significantly higher in chronic LPR patients. The post-treatment decrease of QoL-RSS and RSS of acute LPR patients were significantly faster as compared to recurrent and chronic patients. QoL-RSS >5 reported adequate sensitivity (94.2) and specificity (75.3). QoL-RSS thresholds defined acute (QoL-RSS = 6–25), recurrent (QoL-RSS = 26–38), and chronic (QoL-RSS > 38) LPR. Conclusion: Baseline QoL-RSS may predict the clinical course of LPR patients: acute, recurrent, or chronic. A novel classification system that groups patients according to the longevity, severity, and therapeutic response of symptoms was proposed: the International Federation of Otorhinolaryngological Societies Classification of LPR. Level of Evidence: III Laryngoscope, 2022.