The study was aimed to investigate the effect of RBC K type, PCV, Hb, Na, GSH, AST, ALT and CK concentrations on lambs weights (birth, 2 weeks, 1 months, 1.5 months, 2 months wt, 2.5 months, weaning and weights at 4, 5, 6 and 7 months of age) on 29 male and 21 female Awassi lambs and growth rates during these periods. Blood samples were withdrawn from jugular vein and each sample were divided to 2 parts, the first part were used as whole blood to determine RBC K type, PCV and Hb concentration, while the second part were centrifuged to get blood serum to be used in measuring Na, GSH, AST, ALT and CK concentrations. Data analyzed to determine the effect of RBC K types on lambs growth traits in addition of obtaining simple regression coefficients of Growth traits on blood parameters. The results showed that K type had non-significant effect in Body weights and growth rates during the first 7 months of age. Simple regression coefficients during 1st month of age showed that there is positive significant (P≤0.05) regression for 2 weeks weight on Na concentration and negative significant (P≤0.05) regression on GSH and ALT concentrations. One month and one and half month weights had positive significant (P≤0.05) regression on Na concentration. Body weigh on months of age had positive significant (P≤0.05) regression on Na concentration, ADG had positive significant (P≤0.05) regressions on CK concentration.