We carefully assessed thyroid status and goiter by ultrasound in 1411 subjects virtually representing the entire resident population of Pescopagano, an iodine-deficient village of Southern Italy. Median urinary iodine excretion was 55 microg/L. The prevalence of goiter was 16.0% in children and 59.8% in adults. Thyroid nodularity was 0.5% in children and progressively increased with age to 28.5% in the 56- to 65-yr-old group. The prevalence of present or past hyperthyroidism was 2.9%, including 9 cases with toxic diffuse goiter and 20 with toxic nodular goiter. Functional autonomy was rare in children, progressively increased with age up to 15.4% in the elderly, and was related to nodular goiter. The prevalences of overt and subclinical hypothyroidism in the adults were 0.2% and 3.8%, respectively. Serum autoantibodies to thyroglobulin and thyroperoxidase were detected in 12.6% of the entire population. The prevalence of diffuse autoimmune thyroiditis was 3.5%, being very low in children. Thyroid cancer was found in only 1 case. In conclusion, in the present survey of an iodine-deficient community, a progressive increase with age of goiter prevalence, thyroid nodularity, and functional autonomy was observed. Hyperthyroidism was twice as high as that reported in iodine-sufficient areas, mainly due to an increased frequency of toxic nodular goiter. Although low titer serum thyroid antibodies were relatively frequent, the prevalences of both overt and subclinical autoimmune hypothyroidism were not different from those observed in iodine-sufficient areas.