A retrospective analysis of 117 cases of thyroid cancer diagnosed and/or treated at the Hospital Privado de Comunidad in Mar del Plata, Argentina, between 1974 and 1993 is presented and compared to previously published reports. Mean age at diagnosis was 54.3 years (range 17-88). Follow-up was 8.2 +/- 5.7 years. One third of patients had a previous history of thyroid disease. Histologic types had frequencies comparable to other series: 67.5% papillary, 15.4% follicular, 6% medullary, 3.4% Hürthle-cell and 6.8% undifferentiated. There was one case of lymphoma. Female to male ratio was 4.2:1 (95 females, 22 males). Higher age at diagnosis (over 63 years), higher tumor staging (TNM III or IV) and histologic type (undifferentiated, Hürthle and medullary) were important unfavorable prognostic factors for recurrence or death from the disease, but sex, type of surgery, postoperative radiation and hormonal therapy were not. Undifferentiated carcinomas (n = 8) had 100% mortality (survival 1-17 months after diagnosis, mean 5.5) and Hürthle-cell cancer had 75% mortality (survival 22-46 months, mean 33). Fine needle aspiration biopsy proved to be a useful diagnostic procedure, with an elevated positive predictive value (96%) and a moderate sensitivity (75%). A gradual decrease in surgical complications was observed, the last case of hypoparathyroidism occurring in 1986.