In 2009, the CDC National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP) initiated the online, interactive NCHHSTP Atlas. The goal of the Atlas is to strengthen the capacity to monitor the diseases overseen by NCHHSTP and to illustrate demographic, spatial, and temporal variation in disease patterns. The Atlas includes HIV, AIDS, viral hepatitis, sexually transmitted disease, and tuberculosis surveillance data, and aims to provide a single point of access to meet the analytical and data dissemination needs of NCHHSTP. To accomplish this goal, an NCHHSTP-wide Data Harmonization Workgroup reviewed surveillance data collected by each division to harmonize the data across diseases, allowing one to query data and generate comparable maps and tables via the same user interface. Although we were not able to harmonize all data elements, data standardization is necessary and work continues toward that goal.