Objective To investigate the prevalence and epidemiologic characteristics of hypothyroidism among community population in Jiangsu province. Methods The residents who had lived for at least five years and aged more than 20 years old were sampled from six layers in urban and rural districts of Jiangsu province by a stratified cluster sampling technique. Serum was sampled from 7 122 subjects and sTSH was measured by chemiluminescence immunoassay, and FT3 and FT4 were determined in the subjects with abnormal sTSH level. Results (1) The crude prevalences of overt hypothyroidism and subclinical hypothyroidism were 0.66% and 7.53% respectively in total population, with the respective standardized rates of 0.43% and 6.28%. (2)The prevalences of hypothyroidism and subclinical hypothyroidism were significantly higher in females than in males (both P <0.05). (3) The prevalence of subclinical hypothyroidism was significantly increased with advancing age in both female and males (P<0.05). Conclusion Comparing with hypothyroidism, subclinical hypothyroidism shows higher prevalence in Jiangsu province, and more attention should be paid to the follow-up and diagnosis of subclinical hypothyroidism.