||In this paper, we discuss the architecture and implementation of INDICATOR, a free open source cyberenvironment for disease surveillance. Biosurveillance entails numerous tasks, including data acquisition and preparation, analysis, and reporting. These tasks can be modeled and executed as a workflow. Workflows encapsulate data, tools, and metadata. Cyberenvironments provide integrated, user-friendly sets of tools and services to marshal resources and help researchers analyze, visualize, and model their data. INDICATOR uses an Eclipse-based cyberenvironment that supports interactive workflow creation, connection to data and event streams, provenance tracking, and reuse of workflows and fragments to acquire, analyze, and visualize public health data.