The development, behaviour and temperament of 65 singleton infants conceived through in-vitro fertilization (IVF) and 63 matched controls were compared at 1 year postpartum. Primiparous women were recruited during pregnancy and their infants' development was assessed at 1 year. In addition, test-taking behaviour was evaluated by an examiner using the Bayley behaviour rating scale and mothers completed a behaviour problem checklist and temperament scale. Mental, motor, speech and social development were appropriate for age, with no significant group differences. While receptive language development was in the normal range, IVF infants scored lower than control infants. Across both groups, mothers reported low levels of behaviour difficulty and mean temperament ratings were in the general population range. There were no group differences in observed test-taking behaviour. However, IVF mothers rated their children at a higher level of behaviour difficulty and more reactive than the ratings given by control mothers. Overall, singleton children conceived through IVF demonstrate appropriate general development at 1 year of age. The higher reported behaviour difficulty experienced by IVF mothers may reflect their concerns about the well-being and adjustment of their child during the first year.