Background: Gemcitabine plus cisplatin (GP) is the standard first line chemotherapy for patients with advanced biliary tract cancer (BTC). In the pivotal ABC-02 study, patients received up to 24 weeks (6-8 cycles) of three-weekly GP. In daily practice setting, however, patients without progression often receive GP more than 6-8 cycles. It is uncertain whether maintenance treatment has clinical benefit in patients without progression on GP. Methods: Advanced BTC patients treated with GP between April 2010 and February 2015 in Asan Medical Center, Seoul, Korea, were retrospectively analyzed. Among the patients who did not progressed and stopped GP after 6-8 cycles, patients were stratified according to the further treatment; those with or without further cycles of GP (maintenance group vs observation group). Primary endpoint was overall survival (OS). Results: Among 740 patients, 231 patients (31.2%) were eligible for this analysis; 111 for observation group, 120 for maintenance group. In observation group, 76 patients (68.5%) stopped GP due to completion of scheduled chemotherapy and 27 patients (24.3%) due to the patients’ request or toxicity. There were no statistically significant differences in baseline characteristics between two groups. Median OS from the initiation of GP was 20.5 months [95% CI 15.4-25.6] and 22.4 months [95% CI 17.0-27.8] in the observation and maintenance group, respectively (p = 0.32). Median progression-free survival (PFS) was 10.4 months [95% CI 7.0-13.8] and 13.2 months [95% CI 11.3-15.2], respectively (p = 0.22). These were consistent in the multivariate analyses for OS and PFS after the adjustment of prognostic factors. Conclusions: In our analysis, maintenance therapy of GP was not associated with improved survival outcomes. Considering the potential disadvantages such as cumulative toxicities, maintenance therapy may not be beneficial in patients who did not progressed on 6-8 cycles of GP.