Erythrocytes are readily available cells and a good model system to study the health status of individuals with pathologic complications. It can also serve as a meaningful target to study toxicant/xenobiotic-induced damages. We have prepared different concentrations of a carbamate pesticide (carbofuran) and carried out experiments to determine its toxicity on erythrocytes in terms of mean erythrocyte fragility (MEF). We observed a significant alteration in the osmotic fragility upon treatment with carbofuran. In our earlier studies we have observed a good correlation between OF and OS in diabetic subjects. Study reveals OF as a potential biomarker of oxidative membrane damage in pathologic conditions as well as toxicant/xenobiotic/pesticide-induced oxidative membrane damage to erythrocytes.