Abstract: The difference in Erythrocyte Osmotic Fragility (EOF) and haematologic parameters among two pure (Marshal and Ross) and a Hubbard-Anak cross breeds of 9-week-old broiler chickens were evaluated in this study. There was a statistically significant (P<0.05) decrease in EOF in Marshall breed at NaCl concentrations of 0.5% when compared to other breeds. However, Ross breed had the highest EOF at this NaCl concentration. Haematologic parameters of Packed Cell Volume (PCV), haemoglobin concentration, Red Blood Cell (RBC) count, erythrocytic indices and differential leucocyte counts were not significantly different (P>0.05) among the three breeds. In conclusion, this result revealed a breed difference in EOF and that erythrocyte membranes are osmotically more stable in Marshal breed of broiler chickens.