Twenty-two post-partum riverine buffaloes (Murrah breed) were selected from National Dairy Research Institute (NDRI) Karnal herd of first or second lactation to determine the length of post-partum period for cyclicity commencement by blood metabolites viz., non-esterified fatty acid (NEFA), glucose and alpha amino nitrogen (AAN). Blood samples (5-10 ml) were collected twice a week until commencement of cyclicity as determined by progesterone analysis or for period of 3 months (whichever is earlier). Out of these twenty-two animals, ten were found out to be cyclic as determined through progesterone analysis. Blood samples were collected twice a week at 3-4 days interval from all animals by means of jugular vein puncture 5 days post-partum period. To fulfill the objectives of the present study, plasma NEFA, Glucose and AAN were assayed by Copper soap solvent extraction method modified by Shipe, GOD/POD method and Goodwin method respectively. Plasma progesterone was analyzed by a Direct Radioimmunoassay (RIA) method. Concentrations of blood metabolites viz. glucose and NEFA are unaffected by days for commencement of cyclicity and were also were non-significant (P>0.05).