Background/AimsColon transit time (CTT) is a useful diagnostic tool in chronic constipation, but requires good patient compliance. We analyzed the correlation between the gas volume score (GVS) and CTT in patients with chronic constipation. MethodsThe study included 145 consecutive patients (65 men) with chronic constipation. The primary outcome was the correlation between the colon GVS and CTT. Secondary outcomes were the differences in colon GVS according to CTT and subtypes of chronic constipation. ResultsThere were 81 patients with "CTT < 45 hours" and 64 patients with "CTT ≥ 45 hours." In addition, 88 patients were classified as having functional constipation and 57 were classified as having constipation predominant irritable bowel syndrome (IBS-C). There was no significant correlation between CTT and colon GVS. However, the right colon GVS showed a positive correlation with right CTT (r = 0.255, P = 0.007). The median total colon GVS was significantly higher in patients with "CTT ≥ 45 hours" than in those with "CTT ＜ 45 hours" (5.65% vs 4.15%, P = 0.010). There were no significant differences in colon GVS between the functional constipation and IBS-C. ConclusionsWe were unable to detect a correlation between GVS and CTT in patients with chronic constipation. However, total colon GVS may be a method of predicting slow transit in patients with chronic constipation.