The path analysis for lifetime milk yield of 524 Murrah Buffaloes was done from the data of NDRI herd. The results showed that maximum variability was explained by number of lactations (64%), followed by longevity (51.0%), first lactation milk yield (11.1%), first calving interval (10.6%) and first lactation length (3.8%). The effect of age at first calving was negligible. The maximum of the total effect of number of lactations was due to its direct effect (49.2%), whereas the total effect of longevity was due to its indirect effect via number of calvings and first lactation milk yield. The effects of first lactation milk yield and calving interval were due to indirect effects through number of lactations and first lactation milk yield, whereas the effect of first lactation milk yield was due to its direct effect. The model explained nearly 70 percent of variation by these causal factors.