To compare concomitant therapy (CT) and triple therapy (TRT) for success in helicobacter (H.) pylori eradication and identify factors associated with treatment failure. Quasi-experimental comparative study. Department of Medicine and Gastroenterology, Services Institute of Medical Sciences from December 2018 till July 2019. Patients with H. pylori infection were randomly assigned to receive two weeks of either CT or TRT. H. pylori eradication was confirmed by repeat biopsy four weeks post-treatment. Treatment outcome was compared using Chi-square test, while binary logistic regression identified predictors of treatment failure. Two hundred and eleven patients with H. pylori infection, having mean age 40.15 (±13.04) and male/female ratio 0.9/1 (100/111) after randomisation, were treated with CT in 105 patients (49.8%) and TRT in 106 patients (50.2%). H. pylori was eradicated in 84.3% (150/178) patients with completed follow-up. H. pylori eradication was achieved in 91.9% of CT group as compared to 77.2% in TRT group (p = 0.007, OR 3.38: 95% CI 1.3-8.3). Age ≥40 years (p = 0.02), symptoms duration >6 months (p = 0.001), and prior proton pump inhibitor use for >4 weeks (p = 0.01), were identified as independent predictors of treatment failure. CT achieves better H. pylori eradication than TRT. Older age, longer duration of illness, and previous proton pump inhibitor use were independent predictors of H. pylori treatment failure. Key Words: Concomitant therapy, Eradication, H. pylori, Triple therapy.