This study was conducted to evaluate the effect of some environmental factors on milk production in Egyptian buffaloes and the effect of parity and season of calving on calving interval and days open. There was a significant effect of parity (P ≤ 0.05) on 305day milk yield, while season of calving had a highly significant effect (P ≤ 0.01) on 305day milk yield. Animals with age at first service less than 21 months and age at first calving less than 35 months had higher milk yield than other animals (2489.5 and 2526.7 kg, respectively). With increasing days open, milk production increased so animals had more than 160 days open produced 2757.8 kg milk. Milk yield in winter (2600.5 kg) was higher than in summer season (2441.5 kg). Animals which conceived four or more services produce more milk yield (2529.8 kg). Season of calving had a significant effect (P ≤ 0.05) but parity had a highly significant effect (P ≤ 0.01) on calving interval and days open. There was direct relationship between milk yield with each of calving interval and days open. Animals that gave more than 3000 kg showed the maximum calving interval and days open (14 months and 111.8 days, respectively).