This cohort study assessed all reported injuries experienced by the personnel of a U.S. Navy aircraft carrier during two consecutive 6-month deployments. These nondisease injury cases were collected by the ship's Safety Department from ship's Medical Department reports and showed 291 total injuries (3.05 injuries per 10,000 person-days) and 412 total injuries (4.39 injuries per 10,000 person-days) among 5,101 personnel during two cruises, slightly higher than the recordable mishap rate for general U.S. industry (which uses a different metric). Junior personnel experienced one-half of the mishaps but represented only 31% of the manpower. Slips, trips, and falls were the most common causes of accidents on the ship, similar to general industry. The incidence densities and causes reported should be similar to and representative of those for other large deck ships in the U.S. Navy and can be used in developing risk-reduction strategies for targeted populations, to meet the Secretary of Defense requirement to reduce injuries by 50% in the next 2 years.