There are few well-standardized measures of conversational breakdown in Autism Spectrum Disorders (ASD). The study's objective was to develop a scale for measuring pragmatic impairments in conversations of individuals with ASD. We analyzed 46 semi-structured conversations of children and adolescents with high-functioning ASD using a functional linguistic paradigm. Five constructs were developed that assessed difficulties related to the pragmatics of conversation: atypical intonation; semantic drift; terseness; pedantic speech; perseveration. The scale shows good inter-rater reliability and variation in the scales is not simply a reflection of IQ or language competence. This tool represents a way of characterizing language use in ASD and is an initial step towards developing a tool to evaluate change in degree of social impairments in conversation.