Objective To investigate the riboflavin status of military personnel in heavy labor units, so as to provide the basis for revising the standard of recommended riboflavin intake. Methods Eleven units were selected from different regions. Dietary survey, physical check and 4 h-riboflavin urinary load test were used to evaluate the riboflavin status. Results Dietary riboflavin intake among different units ranged from 1.0 mg to 1.7 mg. Based on 4 h-riboflavin urinary load test, most of the subjects were in insufficient or deficient status while a small number of the subjects were in normal status. Eighteen out of 317 subjects (5.7%) were found to have the signs of riboflavin deficiency. It was calculated that recommended riboflavin intake was 1.8 mg for prevention of riboflavin deficiency. Conclusion The recommended riboflavin intake is 1.8 mg for prevention of riboflavin deficiency in heavy labor units. However, the recommended riboflavin intake for adequacy or sufficiency is remained to be further investigated.