To provide a national-scale picture of the needle exchange program in Taiwan, this study examined (a) needle and syringe program (NSP) service providers' AIDS-relevant harm reduction knowledge and attitudes; and (b) NSP services schemes and operation barriers encountered by different service modalities. A self-administrated questionnaire was mailed to all participating NSP service providers in Taiwan. A total of 414 service providers completed the postal survey. This study confirms that NSP service providers play an essential role in providing comprehensive activities to reduce HIV/AIDS infection for drug misusers. Knowledge and attitudes of service providers were found to be independently and important predictors of NSP service provisions. Community-based and clinical-based providers had diverse service schemes and encountered operation problems due to different organization characteristics, professional training, and ethical concern. For the future planning of NSP programs, service-specific education and professional support are essential component of service delivery and quality.