Missed appointments at specialty clinics generate concerns for physicians and clinic administrators. Appointment nonattendance obstructs the provision of timely medical interventions and the maximization of systemic efficiencies. Yet, empiric study of factors associated with missed appointments at adult specialty clinics has received little attention in North America. We conducted a preliminary study of otolaryngology clinic nonattendance in the context of a universal healthcare system environment in Canada. Our data were based on the schedule of 1,512 new patient appointments at a hospital-based clinic from May 1 through Sept. 30, 2008. Gathered information included the employment status of the attending physician (i.e., full-time vs. part-time), the patient's sex and age, the day of the week and the time of the appointment, and the attendance status. We found that the rate of nonattendance was 24.4% (n = 369). Nonattendance rates varied significantly according to physician employment status (more common for part-time physicians), patient sex (women) and age (younger adults), and the day of the appointment (Wednesdays), but not according to the time of day. Our findings suggest that there are predictable patient and systemic factors that influence nonattendance at medical appointments. Awareness of these factors can have implications for the delivery of healthcare services within a universal healthcare context.