Over the past few years, incidental thyroid microcarcinoma has become a frequent disease and its incidence in some reports is considerable. Discovering new cases depends on the extended indications for total thyroidectomy for benign disease, on progress in the field of diagnostic instruments (ultrasound, scintigram, fine needle biopsy for cytology, CT scan, MRI), and on the pathology examination of very thin slices of specimens. In spite of the high incidence reported in some autopsy series, suggesting that this tumour may have a good prognosis, some Authors report an overall incidence of up to 11% of local recurrence, metastasis or mortality. For all these reasons the surgical treatment of incidental thyroid microcarcinoma is still controversial. The aim of this study was to estimate the incidence and examine the clinical-pathological findings of incidental thyroid microcarcinoma in a series of 100 consecutive thyroidectomies and to evaluate whether complete removal of the gland should be adopted in all cases. In the present series the incidence of incidental thyroid microcarcinoma was 21.6% (19/88). Total thyroidectomy was considered the treatment of choice for diffuse benign disease and appeared to be necessary for both the diagnosis and treatment of incidental thyroid microcarcinoma.