Introduction: Real-world evidence is needed to optimize pharmacotherapy for chronic obstructive pulmonary disease (COPD). The effectiveness of inhaled tiotropium/olodaterol according to baseline symptoms and previous COPD treatment and predictors of response were assessed. Methods: This was a post hoc analysis of a 52-week post-marketing surveillance study of tiotropium/olodaterol in 1255 Japanese patients with COPD of all severities. We analyzed change in total COPD Assessment Test (CAT) score and lung function (forced expiratory volume in 1 s [FEV 1 ] and forced vital capacity [FVC]). Patient subgroups were analyzed based on baseline CAT score (\ 10 [n = 184], C 10 [n = 507]) and previous COPD treatment (treatment-naive [n = 407], previously treated [n = 848], treatment with long-acting muscarinic antagonist monotherapy [n = 161]).Results: In the CAT C 10 subgroup, tiotropium/olodaterol showed statistically significant improvements in mean total CAT score (-6.2; 95% confidence interval [CI] -7.2, -5.1), FEV 1 (0.109 L; 95% CI 0.059, 0.159) and FVC (0.171 L; 95% CI 0.096, 0.245), which continued through Week 52. CAT score and lung function improvement were greatest in treatment-naive patients: -7.6 (95% CI -9.2, -6.1) mean total CAT score, 0.177 L (95% CI 0.076, 0.279) mean FEV 1 and 0.178 L (95% CI 0.036, 0.319) mean FVC. Baseline factors associated with treatment response (total CAT score improvement C 2 points) were: shorter COPD duration (odds ratio [OR] 0.91; 95% CI 0.87, 0.96), total CAT score C 10 (OR 3.86; 95% CI 2.46, 6.06) and treatment-naive status (OR 1.86; 95% CI 1.12, 3.07). Baseline total CAT scores C 13 predicted responses to tiotropium/olodaterol in all previous COPD treatment subgroups including treatment-naive patients. Conclusions: Tiotropium/olodaterol improved symptoms and lung function in Japanese COPD patients. Our results support the possible use of tiotropium/olodaterol in treatment-naive patients and those with total CAT scores C 10. Trail Registration: Clinicaltrials.gov Identifier for parent study: NCT02850978.