The present study is concerned with quantitative analysis of Iodine in drinking water of Nasrya and Kirkuk areas by using amplification reaction s-spectrophotometer method. As a result of the differences in geological setting of both areas, an appreciable increase in Iodine relative to the stations at Nasrya comparison of stations at Kirkuk . The detail analytical data show a decrease in Iodine content during treatment of raw water at the pumping stations of both areas , where as comparison of analytical data points out higher Iodine content ( once and half times ) in drinking water at Nasrya relative to Kirkuk areas .The geographical location of Nasrya area nearby Al-Ahwar region , the sea source of the dominant local foods and the nature of the local soil in addition to higher Iodine content its drinking water, favor reduction in the IDD patients at Nasrya relative to Kirkuk areas . Such conclusion is confirmed by the available statistics of the numbers of IDD patients at both areas during (1985-1990), however , at later period (1991-1997) , this trend of statistics differs noticeably , as showing by the ratio of the number of patient at Nasrya to Kirkuk area ranged between (0.54 - 0.78) compared to ( 0.20 – 0.52 ) during previous period ( 1985 – 1990 ) . The present study discusses the effective factors in in the variation of statistic. Among such factors is the increase in hardness of drinking water at Nasrya area ( 1.196 ml mohs / cm ) compared to ( 0.463 ml mohs / cm ) at Kirkuk area . Sulphide and other elements contributes to the hardness of water , however , its abundance in water leads to reduction of the available Iodine for absorption during human biological processes .