Improvement in trauma patient outcome has been reported after Advanced Training Life Support training (ATLS) in the developing country of Trinidad and Tobago (T & T). The cognitive impact of ATLS training was assessed from pre-ATLS and post-ATLS performance of T & T physicians in multiple choice question tests and comparison with post-ATLS test performance among Nebraska physicians. Overall, improvement between the pre-test and post-test among the T & T physicians was 22.0% +/- 2.0%. All physicians including failures (199 out of 212 passed) improved in their post-test scores. Individual item analysis of the post-test, including the KR-20 determination, varied but the overall performance was similar for both physician groups with the T & T physicians performing slightly better in test 2 (6 of 16 vs. 25 of 100 failures, p < 0.05). Attitudinal impact was assessed through 87 questionnaires from 50 physicians (92% response) and 37 nurses (89% response). Physicians (97.8% compared with 69.7%) were more aware of the ATLS training, and both groups (physicians, 77.3%; nurses, 69.6%) differentiated ATLS-trained physicians based on better resuscitation, more timely and appropriate consultation, greater confidence in trauma management, and improvement in trauma mortality and morbidity; all respondents recommended ATLS training for all emergency room physicians. The demonstrated positive cognitive and attitudinal effects very likely contributed to the improved post-ATLS trauma patient outcome.