Option 2 is an intensive family preservation service for families with serious child protection concerns related to parental misuse of drugs or alcohol. A previous evaluation indicated that it reduced the number of children entering care and, as a result, produced cost savings; however, little data were gathered from families. This study involved interviews with 15 families (46 children) who had received the service, and a comparison group of 12 families (28 children) referred but not provided the service due to no workers being available. Outcomes and experiences were compared, on average, 5.6 years following referral. Findings included a significant reduction in children entering care, and improvements in relation to substance misuse, parental well-being and family cohesion. There was no difference in emotional and behavioural welfare of children. Qualitative accounts were very positive about the impact of the service, identifying effective engagement of parents and key elements of good practice in supporting families to change. The findings provide additional support for suggesting that high quality, intensive interventions with families affected by parental substance misuse can be effective. Key lessons for current attempts to deal with the increase in children entering care and the English government’s ‘troubled families’ initiative are considered.