This paper presents a synthesis about the psychological consequences of twinship based on a review of the literature and on our clinical experience. During pregnancy, delivery and the immediate post-partum, mothers experience physical and psychological difficulties linked with increased medical risks for themselves and for the children. The twins mortality is high before and after delivery. Grieving for one twin creates particular problems for parents. During first months after hospital discharge mothers encounter material and emotional stress. They are caused by overload of mothering tasks and the specificity of mother-twins relationship. The impossibility to establish a dyadic relationship with each child creates feelings of frustration and guilt. The risk of child abuse is increased in twins. The balanced psychoemotional development of twins requires parental attitudes enhancing their individualization as opposed to their "collectivization". The risk of prematurity is ten times increased in twins which increases the risks of developmental disabilities. Considering that the number of twin deliveries is rising in our country it is important to be aware of the problems experienced by the families and to improve the way material and psychological help is provided to them.