OBJECTIVE. Our goal was to identify the frequency, demographics, and diagnostic characteristics associated with maternally reported food allergies and other food-related health problems among infants aged Յ1 year.METHODS. We analyzed data from the [2005][2006][2007] Infant Feeding Practices Study II, a longitudinal survey of 2441 US mothers of healthy singletons from pregnancy through their infant's first year. Doctor diagnosis and symptoms-based criteria were used to identify a probable-food-allergic group from maternal reports of infant health problems with food.RESULTS. More than one fifth of the 2441 mothers reported that their infant had a food-related problem; 6% (n ϭ 143) had a probable food allergy, and 15% (n ϭ 359) had other food-related problems. Forty percent of the infants with a food-related health problem were evaluated by a doctor. Gastrointestinal symptoms were more commonly reported in early infancy compared with skin-related symptoms, which were reported in later infancy, and 27% received medical treatment for the symptoms. Characteristics associated with increased incidence of probable food allergy included family histories of food allergy and type 1 diabetes, gestational diabetes, living in rural or urban areas, being black, and being male. Among all infants with a food-related health problem, the majority experienced their first problem by 6 months of age. Foods recognized to be major allergens were most commonly reported as the source of an allergy.CONCLUSIONS. Food-related problems occurred at a high frequency in the first year of life. A better understanding of the demographics, family history, disease manifestations, and diagnoses may provide insight into public health efforts to minimize or prevent food allergies in infancy and to help differentiate food-allergic problems from nonallergic food problems in this age group. Pediatrics 2008;122:S105-S112 A DVERSE REACTIONS TO foods, which include food allergy, food hypersensitivity, and food intolerance, can result in potentially serious health complications. In particular, immunoglobulin E-mediated food allergies are a leading cause of anaphylactic events treated in hospital emergency departments and can be fatal. 1,2 For reasons that are not well understood, the prevalence of food allergies has been increasing steadily, especially in infants and young children. 3,4 US prevalence estimates of clinically apparent food allergy in this young population are reported to be 6% to 8%, compared with 2% in adults. 5,6 Food allergies are an important component of the allergic march 7 ; it is now recognized that food allergies often precede, and potentially promote, development of other important allergic diseases, such as allergic rhinitis and asthma. [8][9][10] Thus, research efforts aimed at understanding environmental factors, disease manifestations, and other diagnostic features characteristic of food allergies, in relation to other food-related health problems, at this critical infancy stage, may provide important information for publi...