The cue utilization and hypothesis testing strategies of expert reading diagnosticians were examined throughout the diagnostic process. Diagnostic processes of three diagnosticians (a reading specialist, a learning disabilities specialist, and a classroom teacher), who were very different in background and teaching assignment, were studied at work with three girls and three boys (aged 8-11 years). The major data sources included audiotaped and videotaped verbal reports from each diagnostic session, diagnosticians' notes made during the preparation and interaction stages, and the written diagnoses. Selected cues and hypotheses were generally consistent within diagnosticians. These diagnosticians were not as inconsistent as the research of J. F. Vinsonhaler et. al. (1983) indicated. In the entire process, diagnoses and prescriptions were largely consistent, although the diagnosticians may have differed in the process or the labels given the observed reading difficulties. From the examination of cues to the generating and testing of hypotheses, the process tended to arrive at similar results. Eleven figures and two tables summarize data from the experimental sessions. (SLD)