In 2011, the University of Michigan's Center of Excellence in Public Health Workforce Studies and the Association of Public Health Laboratories (APHL) assessed the workforce and program capacity in U.S. public health, environmental, and agricultural laboratories. During April-August 2011, APHL sent a web-based questionnaire to 105 public health, environmental, and agricultural laboratory directors comprising all 50 state public health laboratories, 41 local public health laboratories, eight environmental laboratories, and six agricultural laboratories. This report summarizes the results of the assessment, which inquired about laboratory capacity, including total number of laboratorians by occupational classification and self-assessed ability to carry out functions in 19 different laboratory program areas. The majority of laboratorians (74%) possessed a bachelor's degree, associate's degree, or a high school education or equivalency; 59% of all laboratorians were classified as laboratory scientists. The greatest percentage of laboratories reported no, minimal, or partial program capacity in toxicology (45%), agricultural microbiology (54%), agricultural chemistry (50%), and education and training for their employees (51%). Nearly 50% of laboratories anticipated that more than 15% of their workforce would retire, resign, or be released within 5 years, lower than the anticipated retirement eligibility rate of 27% projected for state public health workers. However, APHL and partners in local, state, and federal public health should collaborate to address gaps in laboratory capacity and rebuild the workforce pipeline to ensure an adequate future supply of public health laboratorians.