Hmong are one of the immigrant Asian subgroups with increasing rates of obesity, type 2 diabetes and CVD. Despite their population growth in the USA and declining health status, no research has investigated the appropriateness of dietary assessment measures, including FFQ and 24 h dietary recalls among Hmong. The present study compared the nutrient information obtained through a 24 h dietary recall method with that collected using the Block Kid's Food Frequency Questionnaire (Block FFQ) among Hmong-American children (n 335) of 9–18 years of age. For this purpose, two 24 h dietary recalls were collected during non-consecutive days and averaged for comparison. The Block FFQ was administered on the day of the second 24 h recall and the two methodologies were also compared using t tests. Among all children, Block FFQ nutrient estimates for vitamin A, vitamin C and food group servings for vegetables and fruits were significantly higher than those assessed through the 24 h dietary recalls (P< 0·001). Nutrient estimates for protein and food group servings for grains and meat and beans were significantly higher among all participants when assessed through the 24 h dietary recalls than through the Block FFQ (P< 0·05). The results suggest that the Block FFQ does not appear to be a good measure of protein, grain, and meat and bean intake among Hmong children of 9–18 years of age, and the 24 h dietary recall offers a better account of the Hmong diet and is inclusive of ethnic food options otherwise missed in the Block FFQ. We recommend the modification of the current Block FFQ to appropriately reflect cultural food/beverage items of the population in interest.