Background: Pneumonectomy is the surgical removal of the entire lung, first performed in 1933 by Evarts A. Graham for lung carcinoma. It is associated with high morbidity and mortality compared to other minimal lung resections. Objectives: The aim of this study is to investigate factors associated with pneumonectomy and its outcome assessment among patients for whom Lung resection done in TASH from January 2017 to December 2022. Methods and Materials: A retrospective Case control study was conducted among 180 patients who undergone pneumonectomy and minimal Lung resection. Data was collected using checklist by trained data collectors. The collected data was entered and analyzed using Statistical Package for social science (SPSS V.25). Univarate, bi-variable and multi-variable analysis were applied to answer the objectives. The Pearson’s chi-square test, COR and AOR were calculated for categorical variables, where appropriate. To identify factors associated with pneumonectomy, binary logistic regression model were computed and Odds Ratio with 95% confidence interval were calculated. A p-value of < 0.25 was used as a cut off points in the crude association to include in to the multivariate analysis. Finally, a p-value of < 0.05 was used to declare significance in the final model. Results: The majority of patients are in the age range of 20-30s, 27 (48.2%) for the pneumonectomy and 41 (33.1%) for the MLR with male to female ration of 1.6:1 and 1.3:1 in pneumonectomy and MLR respectively. 62.5% (35) of the pneumonectomy and 41.9% (52) of the MLR the patient operated for inflammatory conditions while 32.1% (18) of the pneumonectomy and 33.1% (41) of the MLR Carcinoid tumor is the surgical indication whereas Lung Ca is the diagnosis for 5.4% (3) of pneumonectomy and 25.0% (31) for MLR. Emergency admission (AOR, 3.43; 95%CI: 1.28, 8.67), Tb treatment history (AOR, 40.3; 95%CI: 3.01, 540.2), intra operative blood loss > 500ml (AOR, 9.07; 95%CI: 1.04, 79.13), and post-operative complication (AOR, 37.9; 95%CI: 1.82, 792) were identified as associated factors with pneumonectomy. The postoperative complication rate is 25% and 12.1% in pneumonectomy and MLR respectively whereas the mortality is 5.4% and 2.4% in pneumonectomy and MLR respectively. Conclusion and Recommendations: Pneumonectomy is commonly performed for inflammatory conditions in TASH. Emergency admission, Tb treatment history, blood loss, and post-operative complication factors significantly associated with pneumonectomy. Tb prevention, screening strategy and proper patient evaluation and diagnosis before starting on treatment should get an attention at all health facility level.