There is accumulating evidence of a relationship between secure attachment and children's understanding of emotion (Fonagy & Target, 1997; Harris, 1999). The current experiment asked if this relationship is particularly evident when the test of emotion understanding includes attachment-related material or is equally marked on tests with and without attachment-related material. Children ranging from 3-6 years were given a novel test of emotion understanding (the Mother-Infant Separation Test Video) that incorporated provocative attachment themes and also an affectively neutral test of emotion understanding. They performed quite consistently on both types of test - either passing both or failing both. In addition, attachment security, measured concurrently by means of the Separation Anxiety Test, contributed to a correct performance on both tests. This contribution remained when other individual differences were controlled for (age, verbal mental age and gender). Possible explanations of the relationship between attachment and emotion understanding are discussed.