In the current exploratory study a rating scale was devised to assess mothers' and infants' emotional expressions in the natural home context. An examination was made of the stability of emotional expression during the 6–8 month period of the infant's life. Evidence was found for stability of individual differences across a range of maternal but not infant emotions. Significant stability of individual differences was found in dyad's emotional behaviour. In view of the small sample size the present findings should be viewed with caution but the study has identified the need for further research in this field and identified methods which might usefully be used in further studies.