Purpose: The study compared the hypertension care efficacy of a case management intervention program for registered clients. Methods: The nonequivalent control group pretest-posttest design involved 53 registered hypertensive patients of a customized visiting health care service in S-city(n=28 experimental group, n=25 control group). Data collection and case management intervention were carried out from April to July, 2009. The experimental group had six home visits and two phone calls, and the control group had two home visits during the 8-week period. Outcome variables for test hypotheses were changes in physiologic index (blood pressure and total cholesterol) and degree of self-management performance and confidence. Results: Repeated measure ANOVA and t-test of means revealed significant differences before and after program for systolic and diastolic blood pressure and self-management performance and confidence, but no significant difference concerning total cholesterol. Conclusion: A case management program can have positive effects on blood pressure control and self management. However, research is needed to create a more effective case management for vulnerable patient populations.