Purpose Despite increases in formal education, changing trends affecting epidemiologic practice prompted concerns over whether epidemiologists had sufficient training. Methods This study sought to explain factors that predicted low self-reported proficiency levels among daily important work tasks of state health agencies' epidemiologists. The number of knowledge gaps, instances where epidemiologists identified a work-related task both as ‘very’ important in their daily work and felt they were “unable to perform” or performed at a “beginner” level, was studied, and predictor variables were assessed. A total of 681 epidemiologists responded to the 2014 Public Health Workforce Interests and Needs Survey, a national survey of state health agency workers; epidemiologists represented 7% of all respondents. Results Epidemiologists at state health agencies worked mostly in communicable disease (31%) or general surveillance (26%). Epidemiologists reported eight key daily work-related activities with an average of three training gaps. Factors that decreased the likelihood of epidemiologists' low proficiency in performing key activities were the presence of internal trainings (adjusted odds ratio = 0.69, 95% confidence interval, 0.49–0.99) and length of time working in public health (adjusted odds ratio = 0.95, 95% confidence interval, 0.93–0.98). Conclusion Although formal education of epidemiologists is on the rise, state health agencies' epidemiologists feel unprepared to tackle one-third of their important daily tasks.