While Web-based reporting systems are becoming more common in public health for disease surveillance and for tracking interventions such as immunizations, their use for program evaluation is relatively new. This article describes two Web-based reporting systems developed to enable local agencies that conduct health promotion activities to enter process and outcome data for their own use, as well as for analysis by researchers and funders. The systems support the three major uses of evaluation: accountability, program improvement, and generating knowledge for the field. Annually, these programs obtain evaluation information on thousands of clients and individual and group sessions. Developing and introducing the Web-based systems was time-consuming and required significant State Health Department and local agency resources. Involvement of end users in the development process was critical to creating responsive systems that were accepted by staff in local agencies. Staff members from grantee agencies responded well to systems, as evidenced by high rates of user compliance (over 90%) and positive reactions (over 80%) on anonymous surveys. Concerns about resistance from contractors to use of the system, based on fears about breaches in client confidentiality or concerns about the difficulty in using the technology, were not borne out.