Two trials were conducted to assess the blood biochemical and immunity parameters in WL layers (25-44 weeks) at low protein and amino acid supplemented diets. First one is for assessment of digestible lysine and 2nd one is for digestible threonine at constant ratio of other essential amino acids at low protein levels. In experiment –I WL pullets (n=528) were randomly allotted into 11 treatment groups each with 6 replicates of 8 birds and fed with 2 levels of protein (13.36 and 15.78%) with five concentrations of d. lysine (0.50, 0.55, 0.60, 0.65 and 0.70%) and a control group with 17% CP and 0.70% lysine. In 2nd experiment pullets of 390 numbers were distributed into 13 treatment groups with 5 replicates of 6 birds. Basal diets with two d. lysine concentrations (0.65% and 0.60%) at two protein levels (from the experiment –I) and each lysine concentration was supplemented with 6 graded concentrations (60, 63, 66, 69, 72 and 75%) of crystalline threonine, and a control with 17 % CP, 0.70 % lysine and 66% threonine were fed to the birds. Results of these experiments revealed that there was no significant variation in total proteins, albumin globulin, A:G ratio, cholesterol, Alkaline phosphotase, Calcium, Phosphorus and HI titres in both the trials. It indicates that the levels of proteins 13.36 and 15.78% with 0.65%,0.60% lysine at 60% lysine as threonine are optimum for WL layers for production without altering health status.