〔Abstract〕 To explore the correlation between small intestinal bacterial overgrowth (SIBO) and cogni- tive impairment in patients undergoing peritoneal dialysis (PD) . Methods 60 PD patients and 46 non-dialysis pa- tients with end-stage renal disease (ESRD) were included in this study . SIBO was detected by lactulose hydrogen methane breath test (LHMBT) . The cognitive function levels of the subjects were evaluated using the Montreal cog- nitive assessment (MoCA) and mini-mental state examination (MMSE) . The emotional states of the patients were assessed by self-rating anxiety scale (SAS) and self-rating depression scale (SDS) . The gastrointestinal symptoms were evaluated using gastrointestinal symptom rating scale (GSRS) . According to the results of LHMBT , the PD patients were further divided into two subgroups : SIBO-positive and SIBO-negative . The general conditions , labora- tory data , and scores of each scale were compared between the two groups . Furthermore , according to the MoCA scores , the PD patients were divided into two groups : those with normal cognitive function and those with cognitive dysfunction . The positive rates of SIBO between the two groups were compared . Binary Logistic stepwise regression was used to explore whether SIBO was an independent risk factor for cognitive impairment in PD patients . At the same time , other independent influencing factors for cognitive impairment in PD patients were analyzed . Results The positive rate of SIBO in PD patients was 40. 00% . Among them , the positive rate of SIBO in the group with normal cognitive function during peritoneal dialysis was 27. 27% , and the positive rate of SIBO in the group with cognitive dysfunction during peritoneal dialysis was 55 . 56% . There was a statistically significant difference in the positive rate of SIBO between the two groups (P = 0. 026) . Further analysis by multivariate Logistic stepwise re- gression showed that in addition to age (OR = 1 . 118 , 95% CI 1 . 007 - 1 . 242 , P = 0. 037) , educational attainment (OR = 0. 655 , 95% CI 0. 442 - 0. 972 , P = 0. 036) , and hemoglobin( OR = 0. 946 , 95% CI 0. 895 - 0. 998 , P = 0. 044) , SIBO (OR = 7 . 613 , 95% CI 1 . 160 - 49. 979 , P = 0. 034) was also an independent risk factor for cognitive impairment in PD patients . Conclusion The incidence of SIBO in PD patients is relatively high and is associated with multiple factors , among which SIBO may be closely related to cognitive dysfunction in PD patients .