Preterm birth has a critical influence on interactive, communicative, and expressive child behaviour, particularly during the first years of life. Few studies have stressed the assessment of mother-father-child interaction in families with preterm children, generating contradictory results. The present study wished to develop these fields: (i) comparing the quality of family interactions between families with preterm children and families with children born at full term; (ii) observing the development of family interactions after six months in the families with children born preterm; (iii) assessing family and contextual factors, as parental stress and social support, in parents of preterm children in order to observe their influence on the quality of family interactions. 78 families are recruited: 39 families with preterm children (M = 19,8 months, SD = 11,05) and 39 families with full-term children (M = 19,66 months; SD = 13,10). Results show that families with preterm children display a low quality of mother-father-child interactions. After six months, family interactions result is generally stable, except for some LTP-scales reflecting a hard adjustment of parenting style to the evolution of the child. In families with preterm children, the parenting stress seemed to be correlated with the quality of mother-father-child interactions.