Objective: To determine the reliability, validity and correlates of measures of food insecurity (FI) obtained using an individually focused food insecurity access scale (IFIAS) among pregnant women of mixed HIV status in northern Uganda. Design: A mixed-methods study involving cognitive interviews nested within a cross-sectional survey. Setting: The antenatal care clinic of Gulu Regional Referral Hospital. Subjects: Survey respondents included 403 pregnant women, recruited in a ratio of one HIV-infected to two HIV-uninfected respondents, twenty-six (nine of them HIV-infected) of whom were asked to participate in the cognitive interviews. Results: Over 80 % of cognitive interview participants reported understanding the respective meanings of six of the nine items (i.e. items 4 to 9) on the IFIAS. Two main factors emerged from rotated exploratory factor analysis of the IFIAS: mild to moderate FI (IFIAS items 1-6) and severe FI (items 7-9). Together, they explained 90·4 % of the FI measure's variance. The full IFIAS and the two subscales had moderate to high internal consistency (Cronbach's α ranged from 0.75 to 0.87). Dose-response associations between IFIAS scores, and measures of socioeconomic status and women's diet quality, were observed. Multivariate linear regression revealed significant positive associations between IFIAS scores and HIV infection, maternal age, number of children and a history of internal displacement. IFIAS scores were negatively associated with women's diet diversity score, asset index and being employed. Conclusions: The IFIAS showed strong reliability, validity and contextual relevance among women attending antenatal care in northern Uganda. Keywords Food accessPregnancy HIV Food security Uganda AfricaFood security occurs 'when all people, at all times, have physical, social, and economic access to sufficient, safe, and nutritious food that meets their dietary needs and food preferences for an active and healthy life' (1) . Food insecurity (FI) exists when these conditions are not met and is a major underlying cause of undernutrition enshrined in the UNICEF conceptual framework (1,2) . FI is a major risk factor for adverse health outcomes among specific vulnerable populations including persons infected with HIV (3,4) , women (5) and children (5,6) . Women's responsibilities in managing family feeding (7) , gender bias in the experience of FI (8) and unequal control over household resources make them particularly vulnerable to FI and its consequences (3) . Data from the USA indicate that, when faced with FI, women suffer a range of negative nutritional (9) and psychosocial consequences (10,11) .Pregnant women are more likely to experience greater FI than non-pregnant women because they have higher nutrient demands, less physical ability to obtain and prepare food (especially later in pregnancy and early postpartum) and less ability to engage in income-generating labour (10) . The three studies to date about FI among pregnant women have shown that FI has serious negative nutrition...