To determine the stability of appetitive traits during infancy and their association with early life exposures. Participants were from the BiTwin birth cohort (longitudinal study of Portuguese infants). Appetitive traits at 3months were measured using the Baby Eating Behaviour Questionnaire (n = 347) and at 12months with the Children's Eating Behaviour Questionnaire for toddlers (n = 325). Stability was assessed with multi-level models. The association of early life exposures (weight for gestational age, mode of feeding, prematurity, smoking during pregnancy, maternal pre-pregnancy BMI, gestational weight gain, and diabetes mellitus diagnosis) with infant appetitive traits was estimated by multivariable linear regression models. Appetite traits showed limited stability (ICCs: 0.25-0.34). Associations with early life exposures varied by age. At 3months, infants of mothers with higher pre-pregnancy BMI and excessive gestational weight gain had low Satiety Responsiveness. In contrast, infants small for gestational age scored high in this trait (β̂ = 0.241; 95% CI 0.056-0.425). Exclusively formula-fed infants presented weak food approach traits at this age, namely low Enjoyment of Food (β̂ = -0.145; 95% CI -0.270 to -0.019) and Food Responsiveness (β̂ = -0.415; 95% CI -0.618 to -0.212). At 12months, infants who were small for gestational age had low Food Responsiveness (β̂ = -0.297; 95% CI -0.523 to -0.072), in contrast, infants of mothers who gained excessive gestational weight had high scores in this trait. Formula feeding was related to rapid eating (Slowness in Eating: β̂ = -0.252; 95% CI 0.451 to -0.054). Early life exposures may play a role in the development of infants' appetitive traits, which then change during the first year of life. Interventions focussed on maternal and infant health may have the potential to shape appetite in infancy.