To investigate the effect of mindfulness-based cognitive behavioral therapy (MBCT) on peritoneal dialysis patients with insomnia. Methods: Seventy end-stage kidney disease patients receiving peritoneal dialysis who were diagnosed with insomnia were randomly divided into the control group and therapy group, with 35 patients in each. Cases in both groups received sleep hygiene education. Cases in the therapy group additionally received 8 weeks of MBCT. All patients were evaluated by the sleep quality scale (SQS) before and after intervention. The Five Facet Mindfulness Questionnaire (FFMQ) was adopted to assess mindfulness in therapy group patients. The serum albumin (Alb), C-reactive protein (CPR), and urea clearance (Kt/V) in both groups were investigated. Results: After treatment, the Alb and Kt/V in the control group were decreased compared to those before treatment (P<0.05). The CRP in the therapy group was decreased compared to that before treatment and that of the control group (P<0.05). The Kt/V in the therapy group was greater than that of the control group (P<0.05). The therapy group showed an increased score in every component of the FFMQ compared to that before treatment (P<0.05). After treatment, the total SQC score in the therapy group was increased compared to the control group and therapy group before treatment (P<0.05), and the scores of all items of the SQS were increased compared to those before treatment within the same group (P<0.05). Conclusion: MBCT may alleviate insomnia symptoms in peritoneal dialysis patients and may improve the effect of dialysis and reduced inflammation. MBCT can serve as a safe and effective means of psychosomatic therapy.