A study was conducted to examine the relationship between work experience and job knowledge. The data used came from the United States Air Force job performance measurement system (JPMS) database. Data on the cognitive ability and job tenure for two hundred seventy-two aerospace ground equipment specialists (AGE) were used. In addition two measures of task experience were obtained for a sample of 24 AGE tasks. These tasks were subsequently quantified in terms of their difficulty. Hypotheses that work experience predicts job knowledge, and that a task-level measure of work experience, as compared to a job level measure, would be more predictive of job knowledge were supported. In addition, it was shown that both cognitive ability and the difficulty of the task moderates the task experience--job knowledge relationship. Theoretical and practical implications of the findings are discussed.