OBJECTIVE Surgery cancellations cause harm to patients, extra work for preoperative staff, and financial loss for organizations. Day of surgery cancellations are a widely used indicator for operative effectiveness, but there is a lack of knowledge concerning the effects of cancellations during earlier stages of a patient's preoperative waiting period. The purpose of this study was to measure the reasons, frequencies, and timing of elective surgery cancellations after scheduling. METHODS Qualitative prospective follow-up study. METHODS Data were collected during a 2-month period in 13 operative specialties by a semistructured follow-up form and analyzed by inductive content analyses and statistical methods. RESULTS Most of the cancellations occurred before the day of surgery and appeared because patients were not in a suitable condition for the planned operation or because of lack of organizational resources. CONCLUSIONS More attention should be focused on patients' suitability and organizational resources in earlier stages of preoperative period.