Thyroid carcinoma is the most prevalent endocrine tumor. and the papillary carcinoma (PC) is the most common histological type. In the follow-up, after tbyroidectomy serum thyroglobulin (s-Tg) is used as a marker to evaluate recurrence of thyroid carcinoma. In most cases, this parameter allows an adequate diagnosis,. but occasionally s-Tg may miss the detection of a recurrence. We report a 57 year old female and a 36,year old male sujected to a total thyroidectomy for a papillary thyroid carcinoma with intermediate and high-risk of recurrence. Both bad a cervical recurrence without a concomitant increase in s-Tg levels. In both, Tg staining was positive in the tumor cells. These cases confirm that in these patients, the follow-up must be done with measurement of s-Tg and complementary diagnostic tests.