Context: An experimental Health Care Improvement Program (HCIP) was initiated by the Bureau of National Health Insurance in 1997 to improve the accessibility of health care in several rural, mountainous districts. Purpose: This longitudinal study evaluated service availability, utilization patterns, and effectiveness of services under the HCIP in the A-Li Mountain District. Methods: Outpatient claims made by residents in the A-Li Mountain District were extracted from the database of the National Health Insurance program. Changes in utilization pattern and volume were analyzed. Satisfaction levels were assessed by 2-stage face-to-face interviews with local residents. Findings: After the HCIP, the average population served by each doctor decreased 75%, and total outpatient visits increased 15.4%. The total number of in-district outpatient visits increased 83.6%. The proportion of in-district outpatient visits to all visits increased from 22.1% to 35.1%. The total in-district outpatient visit fee claimed increased 100.2%, and the total out-of-district outpatient visit fee claimed increased only 7.2%. About 60.4% of the residents were not satisfied with overall health care services before the HCIP. The proportion decreased to 32.4% after the HCIP. Conclusions: The HCIP improved accessibility, enriched local medical care resources, changed the utilization pattern of some residents, and increased residents' satisfaction level. A well-managed program with stabilized financial resources is more likely to succeed if it also respects cultural differences and responds to community needs.