The objective of this study was to examine the extent of underreporting of total energy intake and associated factors in a low-income, low-literacy, predominantly Caribbean Latino community in Lawrence, MA. Two hundred fifteen Latinos participated in a diabetes prevention study, for which eligibility included a >or=30% risk of developing diabetes in 7.5 years. Dietary self-reported energy intake was assessed using three randomly selected days of 24-hour diet recalls. Basal metabolic rate (BMR) was estimated using the Mifflin-St Jeor equation. Underreporting was determined by computing a ratio of energy intake to BMR, with a ratio of 1.55 expected for sedentary populations. Linear regression analyses were used to identify factors associated with underreporting (energy intake:BMR ratio). The population was predominately women (77%), middle-aged (mean 52+/-11 years), obese (78% had a body mass index >or=30); low-literate (62% < high school education), unemployed (57% reported no job), married or living with partner (52%), and some had a family history of diabetes (37% had siblings with diabetes). Reported total daily energy intake was 1,540+/-599 kcal, whereas estimated BMR was 1,495.7+/-245.1 kcal/day. When multiplied by an activity factor (1.20 for sedentariness), expected energy intake was 1,794+/-294.0 per day, indicating underreporting by an average of 254 kcal/day. Mean energy intake:BMR was 1.03+/-0.37, and was lower for participants with higher body mass index, siblings with diabetes, sedentary lifestyle, and those who were unemployed. Energy intake underreporting is prevalent in this low-income, low-literacy Caribbean Latino population. Future studies are needed to develop dietary assessment measures that minimize underreporting in this population.