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The aim of this study was to develop a procedure to adjust lactations of longer duration to a standard such as 305-days when standard lactation milk yield for such lactations could not be recorded. For Sahiwal cattle and Nili-Ravi buffaloes, information on completed lactations for duration of more than 305-days was used for 3054 and 3927 lactations, respectively. Final regression equations to predict standard lactation milk yield (305-day milk yield) (SLMY) from completed lactation milk yield (CLMY) and lactation length (LL) were obtained using multiple regression analysis.SpeciesRegression equationsR2 (%) VIFSahiwal CattlePredicted SLMY = 1239 + 0.967 (CLMY) - 3.80(LL)96.5 0.035Nili-Ravi BuffaloesPredicted SLMY = 1604 + 0.925 (CLMY) - 4.75 (LL)96.1 0.039Thus, standard lactation milk yield can be fairly adequately predicted from total milk yield of longer lactations and lactation length using linear regression technique both in Sahiwal cattle and Nili-Ravi buffaloes with reasonable accuracy.