This study explored the salient characteristics of transactions within parent-child engagement and investigated relationships between transactional characteristics and future identification of autism. The main aims of the study were to (1) examine if parents/children and their initial behaviors impact the length of transaction; (2) determine miscue differences among parents and children; and (3) determine if transactional characteristics are predictive of autism at preschool age. The study sample was drawn from extant data of a parent-mediated intervention for young children showing early sings of autism. Thirty parent-child dyad videos were randomly selected and coded for transactions. Statistical analyses were applied to examine the study aims and to perform post-hoc analyses. The length of transaction increased when children initiated with a look cue. Parents displayed a higher proportion of miscues and greater variance in their miscue behavior than their children. Neither the length of transaction nor the proportion of child miscues at 1-year of age predicted an autism diagnosis at preschool age. Post-hoc analyses revealed that girls with high variance of transaction length at 1-year of age, had a lower likelihood of showing autism traits at preschool age. Sustained transactions were more likely when children initiated engagement by looking. Early transactional characteristics were associated with later autism identification among girls, namely longer median transaction length with lower variance of transaction length. This transaction profile is believed to represent high fixation on topics with less ability to explore varied topics.