We report and describe the clinical findings of three patients who developed atonic pupil after uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens implantation. All patients had normally reactive pupils one day postoperatively, but after two weeks, the pupils were dilated and nonreactive to light, accommodation, and miotics. To estimate the incidence of atonic pupil after cataract surgery, we sent a survey on the frequency, clinical features, and possible etiologies of this syndrome to members of the American Society of Cataract and Refractive Surgery. Of the 567 respondents, 60% had seen at least one case of atonic pupil in the past five years; they reported a total of 1543 cases during that time. This is probably a conservative figure since many cases undoubtedly go unnoticed because of a lack of visual disturbance. We believe this condition occurs more frequently than previously reported. The atonic pupil should be recognized as a possible complication of cataract surgery that should be included in the preoperative consent form.