Introduction: This study aimed to determine the efficacy of Mindfulness-Based Cognitive Therapy (MBCT) on the depression and sleep quality of dialysis patients. Methods: The research methodology was a quasi-experimental design employing a pre-test, post-test approach with a control group. The statistical population comprised all dialysis patients at Shafa Hospital in Kerman during the year 1403 [Persian Calendar]. From this population, 30 patients (15 in the experimental group and 15 in the control group) were selected using convenience sampling. Data collection instruments included the Beck Depression Inventory (BDI) (1961) and the Pittsburgh Sleep Quality Index (PSQI) (1989). The intervention, Mindfulness-Based Cognitive Therapy (MBCT), was administered to the experimental group in 8 sessions, each lasting 60 minutes, twice a week, for a specified duration. The control group received no intervention. Data analysis was performed using descriptive statistics (mean and standard deviation) and Analysis of Covariance (ANCOVA) via SPSS software, version 24. A significance level of P<0.05 was considered. Findings: The results indicated that Mindfulness-Based Cognitive Therapy was effective in reducing depression and improving the sleep quality of dialysis patients at the post-test stage (P<0.01P < 0.01P<0.01). Conclusion: Based on the research findings, Mindfulness-Based Cognitive Therapy can be utilized to decrease depression and enhance the sleep quality of dialysis patients. Keywords: Mindfulness-Based Cognitive Therapy, Depression, Sleep Quality, Dialysis Patients.