This study was a cross-sectional, descriptive, correlational study. Research aims were: (a) to understand peritoneal dialysis patients’ self-care efficacy, self-care behavior, and treatment outcomes, and (b) to examine the relationships between patients’ treatment outcomes and individual characteristics, disease-related characteristics, self-care efficacy, and self-care behavior, and (c) to explore possible factors related to patients’ treatment outcomes. The 200 subjects of this study were recruited from the peritoneal dialysis centers at two medical centers and two regional hospitals in Taipei. Self-developed questions, CAPD self- efficacy scale, CAPD self-care scale, the Taiwanese world organization quality of life-BREF, and patients’ medical records were used to collect the related information. Data analyses were completed by descriptive statistics, Pearson’s correlation, one way ANOVA, independence t test, enter multiple regression and Logistic regression. Study results showed the mean scores of the peritoneal dialysis patients’ self-care efficacy and self-care behavior were 208.75±28.09 (range = 0~250) and 219.13±30.07 (range = 0~250), respectively. The result of CAPD self- efficacy factors, the highest score was found at the managing abnormal conditions factor, and the lowest score was found at the adjusting life style. The result of CAPD self- behavior factors, the highest score was found at the caring for the catheter exit site factor, and the lowest score was found at the adjusting life style. The mean score of peritoneal dialysis patients’ quality of life was 91.88±14.81 (range = 28~140). With the highest score was found at the environment domain, and the lowest score was found at the psychological domain. The majority treatment outcomes were within the standard levels recommended by the National Kidney Foundation: Kt/V 2.08±0.47 (recommendation: >1.7), serum albumin 3.90±0.52 gm/dl (recommendation: > 4.0gm/dl), hematocrit 30.82±4.70% (recommendation: 33-36%), and nPNA 1.03±0.23 gm (recommendation: > 0.9gm). Study results also showed peritoneal dialysis patients’ treatment outcomes were associated with dialysis institution, gender, age, religion, personal income, family income, co morbidities and self-care efficacy. Confirming the possible factors related to peritoneal dialysis patients’ treatment outcomes could help policy makers constitute appropriate health care policies and help clinical healthcare providers develop related health promotion interventions. In order to improve patients’ treatment outcomes, the following strategies could be utilized: accomplishing related social welfare policy, providing professional personnel’s continuing training/education, conducting patient individual/group consult, constructing patient support groups, and delivering patients’ retraining program.