Verbal marking of affect by older children with Asperger Syndrome (AS) and high functioning autism (HFA) during spontaneous interactions is described. Discourse analysis of AS and HFA and typically developing children included frequency of affective utterances, affective initiations, affective labels and affective explanations, attribution of affective responses to self and others, and positive and negative markers of affect. Findings indicate that children with AS and HFA engaged in a higher proportion of affect marking and provided a higher proportion of affective explanations than typically developing children, yet were less likely to initiate affect marking sequences or talk about the affective responses of others. No significant differences were found between groups in terms of the marking of positive and negative affect.