Background: Endoscopic thoracic sympathectomy (ETS) is renowned as an effective surgical treatment for primary hyperhidrosis (PHH) and believed to improve patients’ quality of life (QOL). This study aimed to evaluate the quality of life (QOL) of patients with PHH after ETS compared to before ETS, and to determine whether compensatory sweating (CS) affects QOL of patients. Methods: This is a single-centre retrospective review of patients who had undergone ETS at the National Heart Center [Institut Jantung Negara (IJN)], Malaysia. In total, 62 patients from January 2014 to December 2018 were recruited. Medical records were first reviewed for all relevant data, prior to making telephone interview to administer the questionnaire. A modified questionnaire with validated components was used to assess the patients’ QOL. Patient satisfaction, symptom resolution, recurrence and occurrence of CS were also asked during the interview. Data were analysed using IBM SPSS Statistics 25.0. Results: A total of 46 patients (response rate: 74.2%) completed the questionnaire, with 95.7% reporting improvement in the total QOL score (Mean difference = 113.54, SD=70.79, 95% CI = 95.52 – 134.57, p<0.001). There was remarkable symptom resolution for palmar HH as 97.8% reported dry hands, whereas majority of patients with palmar-plantar HH reported persistent sweating from feet HH. CS rate was 89.1%. In terms of severity of CS, 6 (14.6%) reported mild, 17 (41.5%) moderate, and 18 (43.9%) had severe CS. The severity of CS as well as the number of locations have a significant effect on the QOL reported (p=0.022 and p=0.008, respectively). Conclusion: ETS is an effective treatment for PHH in improving the QOL of patients, even long term. The occurrence of CS did not affect the QOL, but severity of CS and number of locations involved in CS affect the QOL of patients.