Selected optimal conditions for production of prodgiosin for pathological and environmental isolates of the bacterium Serratia marcescens which was isolated from pathological and environmental sources, the results showed that the peanut powder medium at 2% concentration was the highest production of pigment under the conditions of pH 8, volume 50 ml from the medium in 250 ml conical flask at 28 ºC for 72 hrs without light.