The increased emphasis on investing support for families before children enter school has increased the need for assessment tools that support and encourage positive parenting. Identifying the positive parental behaviours that promote healthy child development is challenging as many of the current observational codes have been designed for parents? interactions with older children. This article describes the development of a new observational code to analyse the behaviour of mothers playing with their baby in the first 18 months. The six predetermined positive parenting behaviours are analysed using video recordings from the home. Practitioners can be trained to use the code and a manual facilitates future researchers and clinicians to evaluate parent behaviour with their infant in a natural environment and with minimal disturbance to the family.