Data on fatal occupational injuries (FOIs) for Latin America are controversial. Costa Rican national rates are inconsistent with estimates extrapolated from other countries. We reviewed the files for all possible FOIs in Costa Rica for 2005-2006 at the National Insurance Institute and at the Center of Forensic Sciences by formality/informality of work, sex, age, economic activity, occupation, and cause of death. The national mortality rate was estimated at 9.5/100,000 person-years (342 deaths). The informal/formal rate ratio was 1.06. Men's rates were over 10 times higher than women's and increased with age. The highest rates were found for transport, storage, and communication (32.1/100,000 person-years), and, by occupation, for messengers and delivery men (91.4). Leading causes of death were traffic injuries and gunshots. Recalculated rates are probably underestimates. Data limitations include the absence of systematic identification and registration among informal sector workers and other groups such as children and farm workers.