Excessive iodine exposure was reported to be associated with thyroid dysfunctions. The aim of this study is to evaluate the link between excess urinary iodine as the prime indicator of excessive iodine intake and autoimmune subclinical hypothyroidism (SCH) among Egyptian women. Seventy three women with autoimmune SCH and 60 age- matched healthy women as controls were enrolled in this study. TSH, FT4, urinary iodine concentrations (UIC) and thyroid peroxidase antibody (TPOAb) were estimated. The levels of urinary iodine were significantly higher in patients with SCH as compared with control subjects, (326.97 112.98 vs. 274.45 98.75 microg/l, p<0.01). In patients with SCH, there was a significant correlation between UIC and TSH levels. Also, a significant correlation between UIC and TPOAb was found. We conclude that excessive iodine intake may trigger thyroid autoimmunity and eventually thyroid hypofunction among Egyptian women.