Arsenic exposure to humans is pervasive, and, increasingly, studies are revealing adverse health effects at ever lower doses. Drinking water is the main route of exposure for many individuals; however, food can be a significant source of arsenic to an individual, especially if their diet is rice-based. Infants are particularly susceptible to dietary exposure, since many first foods contain rice and they have a low body mass. Here we report on arsenic concentration and speciation in infant formulas and first foods. Speciation is essential for food analysis because of the much greater toxicity of inorganic arsenic species and the possibility that arsenic in food (unlike water) may be present in either inorganic or organic forms. Infant milk formulas were low in total arsenic (2.2-12.6 ng g(-1), n=15). Non-dairy formulas were significantly higher in arsenic than dairy-based formulas. Arsenic in formula was almost exclusively inorganic and predominantly arsenic(V). Arsenic concentration in purees (n=41) and stage 3 foods (n=18) ranged from 0.3-22 ng g(-1). Rice-fortified foods had significantly higher total arsenic concentrations than non rice-based foods. Again arsenic speciation was predominantly inorganic; arsenic(III) was the main species with lower concentrations of DMA and arsenic(V) also present. These data confirm that infants are exposed to arsenic via diet, and suggest that careful attention to diet choices may limit this.