Objectives Audio-video recording of pediatric clinic visits could generate observational reactivity, affecting measures of communication among patients, parents, and clinicians. Methods We measured observational reactivity in a direct observation study of communication during 155 pediatric visits for any of 5 chronic conditions by coding camcorder awareness behaviors and self-report questionnaires. We analyzed associations between observational reactivity and measures of communication behavior and visit quality. Results Directly observed camcorder awareness behaviors (634 events) comprised 0.59% of all coded events (n = 107,668). Younger children displayed these behaviors more often than did older children (F = 6.47; p < .0001). Clinicians’ camcorder awareness declined significantly over successive study visits (t = −2.096; p = .043). Associations of camcorder awareness with objectively scored communication behaviors or self-reported visit quality were negligible. Conclusions Most recordings included slight evidence of participant camcorder awareness. But there was negligible evidence that camcorder awareness influenced clinic visit communication. [ABSTRACT FROM AUTHOR]