Effects of continuous and over dosage of salinomycin was studied experimentally in layer chicks. Salinomycin was given to layers @ 60, 120 and 180 ppm in feed up to the age of 12 weeks. During the course of trial, the birds of all groups were active and did not show any clinical signs. Body weight started decreasing significantly (P<0.001) in chicks receiving 60, 120 and 180 ppm salinomycin compared to the control group from the 11^th, 5^th and 3^rd  week onward, respectively. Feed conversion ratio at 12^th week was 3.537 in the control compared with 3.701, 4.250 and 4.465 in layer chicks given salinomycin at the rate of 60, 120 and 180 ppm, respectively. Absolute weight of liver at 12^th week and absolute weight of kidneys throughout the experiment decreased significantly (P<0.001) in chicks receiving 180 ppm salinomycin. Concentrations of AST,  ALT, blood urea and creatinine were higher in layers receiving 180 ppm salinomycin, while serum total bilirubin concentration was increased significantly (P<0.001) in layers receiving 120 and 180 ppm salinomycin. No gross lesions were observed in liver and kidneys of layers receiving various doses of salinomycin. Microscopically, there was congestion of liver sinusides and vacuolization of hepatocytes in chicks receiving 180 ppm salinomycin. There was hydropic degeneration of tubular epithelium, degeneration and desquamation of most of cells of Bowman’s capsule epithelium of kidneys in birds receiving 180 ppm salinomycin. Higher doses of salinomycin seem to alter liver and kidney functions subclinically in layer chicks.