
Introduction: Arsenic is naturally occurring element that is widely distributed in nature. The main source of exposure for the general population is intake of drinking water with high level of arsenic. There is evidence of fetal loss & infant mortality due to arsenicexposure of mother by drinking water that may be due to arsenic crosses the placenta. Breast milk is main source of nutrition during 1st 6 months of life. There are few reports of low concentration of arsenic in breast milk. Urinary arsenic is considered as dependable marker of ongoing contamination. Arsenic level in urine of exclusive breastfed baby shows the intake of arsenic through breast milk. Objective: To detect arsenic secreted through breast milk from arsenic affected mother by measuring urinary arsenic level. Methods: It was a case-control prospective study. From January 2008 to July 2009 this study was done in Laksam thana in Bangladesh. Total 80 exclusively breast fed babies were enrolled in this study, 40 babies were cases whose mother were arsenic affected &40 babies of control group were nonaffected mother. To detect arsenic concentration in breast milk we considered as arsenic level in urine. We thoroughly examine mothers& their babies. Results: In this study total 80 breast fed babies were enlisted, 40 from affected mother & 40 from non-affected mother. Arsenic affected mothers showed 100% melanosis &27.3% keratosis .Arsenic concentration in urine in affected mother (case) was 329.57microgram/L±106.017 & median was 379.67 micro gm/l, arsenic level in urine of baby of affected mother (case) is7.02±1.05. In control group both mothers urinary arsenic level& babies urinary arsenic level were low. Physical growth & milestone of development were normal in both group of babies. Conclusion: All Arsenic affected lactating mother should continue their breast feeding exclusively without harm to their babies.