Objective To investigate the sleep features in the patients with irritable bowel syndrome (IBS) and compare the sleep quality between those IBS patients who were with and without anxiety and depression.Methods Pittsburgh sleep quality index questionnaire (PSQI), self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were measured in the 145 IBS patients and 59 regular physical examination volunteers.IBS patients were also divided into two subgroups-patients with or without anxiety and depression based on cutoff scores of SAS and SDS.Comparisons of sleep quality were made between subgroups, and between IBS patients and volunteer controls.Results Compared with the controls,the SAS raw score, SDS raw score and SAS positive incidence in IBS patients were shown statistically significant differences (P ＜ 0.05 ), while the SDS positive incidence had no statistically significant difference(P ＞ 0.05 ).PSQI total scores were significantly higher in the IBS patients without anxiety and depression (P ＜ 0.05), 3 domains (sleep quality, sleep disturbances and daytime function disorder) were also found statistically significant differences ( P ＜ 0.05 ), compared with the controls.The IBS patients with anxiety and depression were statistically significantly different from the controls ( P ＜ 0.05 ) in 6 domains (sleep quality, sleep latency, sleep efficiency, sleep disturbances, sleep time and daytime function disorder) and significantly higher PSQI total scores( P ＜ 0.05 ).Statistically significant differences (P ＜0.05) were also found in all 7 domains and with higher PSQI total scores in IBS patients with anxiety and depression, compared with IBS patients without anxiety and depression.Conclusions IBS patients were more likely to have sleep abnormality, mainly in sleep quality, sleep disturbances and daytime function disorder and PSQI total scores.The abnormalities of these factors were independent of emotional disorder.However, emotional disorder worsened the sleep disorder in IBS patients.