['Despite long standing iodine supplementation in Iran the prevalence of goiter remains high in some areas. In the present study we investigated the possible role of thiocyanate as a goitrogen in the etiology of goiter in Isfahan, Iran.', 'A total of 2331 (6-13 year old) school children were selected by multistage random sampling. Thyroid size was estimated in each child by inspection and palpation. Urinary iodine concentration (UIC) and urinary thiocyanate (USCN) were measured.', 'Overall, 32.9% of the 2331 students had goiter. The median UIC was 195.5 μg/L. The mean ± SD of USCN in goitrous and nongoitrous subjects was 0.42 ± 0.28 mg/dL and 0.41 ± 0.32 mg/dL, respectively (P=0.86). USCN level in goitrous and nongoitrous boys was 0.41 ± 0.32 mg/dL and 0.43 ± 0.37 mg/dL, respectively (P=0.67). USCN level in goitrous and nongoitrous girls was 0.43 ± 0.26 mg/dL and 0.40 ± 0.28 mg/dL, respectively (P=0.43).'] Does thiocyanate status play a role in the etiology of residual goiter in school children of Isfahan , Iran?