54 Background: We aimed to retrospectively analyze the efficacy and toxicity of capecitabine, as a salvage treatment, in metastatic colorectal cancer (mCRC) that progressed after prior standard 5FU included chemotherapies. Methods: From January 1, 2008, to December 31, 2017, patients with mCRC, age ≥ 18, who received capecitabine as third- or fourth-line treatment at five different centers in South Korea, were included. All had disease progression on prior palliative chemotherapies including 5FU, oxaliplatin, and/or irinotecan. Results: A total of 131 patients were analyzed with a median age of 62 (range, 35-87). Almost all patients were exposed to prior 5FU (100%), irinotecan (100%), and oxaliplatin (98.5%). Patients were treated with cetuximab (26.7%), or bevacizumab (45.8%) before capecitabine. The median and mean duration from the last 5FU exposure to capecitabine start were 21 and 67.3 days, respectively (range, 5-1322). The objective response rate (ORR) of capecitabine was 3.6%, and the disease control rate was 30.4%. The median progression free survival (mPFS) and median overall survival (mOS) was 2.77 (95% CI, 2.495-3.045) and 9.60 months (95% CI, 7.625-11.575), respectively. There was a significant difference in efficacy according to the duration from the last 5FU exposure to the time of starting capecitabine. Compared to patients who started capecitabine earlier than 67 days after the last 5-FU administration, those who started capecitabine later than that time showed higher ORR (11.1% vs 1.2%; p-value = 0.043), mPFS (4.430 (95% CI, 2.274-6.586) vs 2.570 months (95% CI, 2.326-2.814); p-value = 0.011), and mOS (14.070 (95% CI, 5.627-22.513) vs 9.500 months (95% CI, 7.370-11.630, p-value = 0.021) (Table). 68.7% patients experienced any grade of adverse events, but only 4.6% complained grade 3 or higher. There was no treatment related death. Conclusions: Capecitabine showed modest antitumor activity with good tolerability in mCRC patients whose disease progressed after oxaliplatin and/or irinotecan. It could be considered as an alternative treatment option for mCRC patients, especially for those who have longer treatment free interval after 5FU based chemotherapies. [Table: see text]