This study aimed to develop a mobile application for improving self-management and to evaluate its effects in adult patients on peritoneal dialysis (PD). This randomized controlled trial was registered with the Korean Clinical Research Information Service Registry (KCT0007267) and conducted at a tertiary hospital. A self-management mobile application (SMA) was developed based on social cognitive theory and the ADDIE (analysis, design, development, implementation, and evaluation) model. The SMA includes information about disease management; self-recording of data on diet, exercise, medication, and health behavior; and healthcare providers' support and feedback. Participants aged 19-65 years were randomly allocated to the intervention group (n = 27) using the SMA for 10 weeks, and the control group (n = 26) receiving usual care. PD-related knowledge and self-efficacy, PD-related health behavior, biomarkers, and health-related quality of life (HRQoL) were surveyed pretest/posttest and analyzed using SPSS 23.0. Compared to the controls, the intervention group showed significant improvement in PD-related knowledge and health behavior, albumin, and hemoglobin. HRQoL domains of symptoms/problems of kidney disease and disease impact on daily activity were improved in the intervention group. The SMA is an effective intervention for enhancing health behaviors as well as improving the HRQoL of patients with PD. Without any limitations on time or location, patients with PD can easily use the SMA to monitor their health conditions, efficiently manage their disease, and perform PD-related behaviors. Nurses can implement high-quality tailored healthcare by using patients' lifelog data from the SMA.