Information technology (IT) use for epidemiological purposes in state public health departments has been documented only for a limited number of specific applications, leaving questions about its actual utilization and hindering IT's potential for information sharing. Communications, stages of change, and systems theories all influence the use of IT applications and were used as the theoretical framework for this study. An observational, cross-sectional design was used to survey 59 state public health departments to determine the current state of IT usage with barriers to implementation and timeliness of data availability. Survey responses were received from 17 departments. Chi square and Fisher's exact test were used to examine the relationship between IT usage and timeliness of data availability as well as barriers to implementation. Results showed IT applications are currently implemented for less than 50% of the epidemiological functions (Bioterrorism/Emergency Preparedness, Chronic Disease, Environmental Health, Infectious Disease, Injury, Maternal and Child Health, Occupational Health, and Oral Health) being performed across all departments and that there is a significant association between the use of IT applications and a reduction in the time to data availability for 6 of the 8 epidemiological functions. Chronic Disease and Environmental Health functions did not show a significant association. Budget and priorities in the department were found to be significant barriers to implementation of IT functions. The findings provide support for positive social change by identifying the benefit of IT usage to allow more timely data for epidemiological activities, which can improve health outcomes and quality of life for those served by the state public health departments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]