This study was conducted to investigate the effect of lead acetate-polluted diet ingestion on some biochemical, immunological and physiological parameters of laying hens, and try to employ some useful properties of clay for reducing the adverse effect of lead and its accumulation in eggs and tissues. For this purpose 180 Gimmizah laying hens at 38 weeks were randomly distributed equally into nine treatments:-control, control+250ppm pb, control+250ppm pb+2.5% clay, control+250ppm pb+5% clay, control+500ppm pb, control+500ppm pb+2.5% clay, control+500ppm pb+5% clay, control+2.5% clay and control+5% clay. Blood total protein, albumin, globulin, total calcium, phosphorus and the activity of some enzymes (GOT, GPT and ALP) as well as egg, liver and muscle lead residues were determined for two times. The first time after the positive experimental period, the second after the negative experimental period. Also hemoglobin and antibody titer were determined for one time only (After the first). Results obtained for the first period indicated that, lead-polluted diets significantly decreased plasma total protein, total calcium, hemoglobin, GPT, GOT and ALP activity and antibody titer values. However, the levels of albumin, globulin and phosphorus were not significantly affected by feeding lead polluted diets. Lead residuals were accumulated in a dose-dependent manner. The highest lead deposition occurred in liver, while the lowest was in muscles. Adding clay to lead-polluted diets significantly reduced the adverse effect of lead on the previous parameters and reduced lead retention in egg, liver and muscles. After the negative experimental period all the previous parameters were go back around their normal ranges. The concentrations of lead residue in egg, liver and muscles were reduced to that of the control group. It could be recommended that, adding the natural clay at level of 5 % to layer diet contaminated with lead can prevent the adverse effect of lead .