['Many authors advocate total or near-total thyroidectomy for thyroid carcinoma. This study examined the relationship between hospital volume of thyroidectomies and choice of bilateral thyroidectomy for thyroid carcinoma.', 'Data were extracted from the administrative databases of all hospital discharge abstracts in the Rhône-Alpes area of France. The study population included inpatient stays from 1999 to 2004 with a diagnosis of thyroid disease (benign or malignant) and a procedural code for thyroid surgery. Multivariable logistic regression analyses were performed to determine factors associated with the extent of surgery (unilateral versus bilateral) for thyroid carcinoma.', 'A total of 20 140 thyroidectomies were identified, including 4006 procedures for cancer. Compared with hospitals performing a high volume of procedures for all thyroid diseases (at least 100 annually), the risk of a unilateral procedure for thyroid cancer increased by 2.46 (95 per cent confidence interval 1.63 to 3.71) in low-volume hospitals (fewer than ten operations per year) and by 1.56 (1.27 to 1.92) in medium-volume centres (ten to 99 per year).'] Does hospital volume influence the choice of operation for thyroid cancer?