On hundred and sixty babies of birth weight less than or equal to 1500 g who survived after perinatal intensive care have been followed up and observations have been made on their parents. In spite of attempts to minimize maternal separation and the distressing aspects of the birth and management of a baby of very low birth weight, an emotional crisis was observed in the mothers which was not fully resolved until the parents had been looking after the baby at home. The duration and degree of the crisis varied but the mothers who received sympathy and support from the baby's father appeared to have least difficulty. A rigid maternal personality and circumstances surrounding the birth which predisposed to feelings of failure and guilt appeared to prolong the crisis. Nevertheless, most of these parents subsequently formed satisfactory relationships with their children, although they tended to be over-protective and anxious. Failure to establish an adequate relationship was rare and occurred only among mothers with personality or psychiatric disorders. Although serious behaviour disorders among the children were rare, more children than would be expected were mildly over-dependent, shy and anxious at follow-up.