Water buffaloes (Bubalus bubalis) are mainly distributed in tropical and subtropical countries including Egypt. The transition period is the most stressful period, and it is considered as a turning point in the productive cycle from one lactation to the next and includes different metabolic, physiological, and nutritional changes. Metabolic disorders are common causes of lower productivity in buffaloes. This study aimed to study the ketosis- and hypocalcemia-related biochemical changes during the transition period and their impacts on the postpartum reproductive fertility in Buffaloes. Out of 120 total number of examined buffaloes, 40 buffaloes were used in this study control group (n=10), hypocalcemia-affected (n=15), and ketosis-affected group (n=15). All buffaloes were subjected to thorough clinical and gynecological examination. Both urine and blood samples were collected from all groups. The amounts of ketone bodies were detected in urine. Biochemical parameters were evaluated including concentrations of glucose, triglycerides, cholesterol, non-esterified fatty acids (NEFA), calcium, phosphorus, sodium, potassium, albumin, total protein, urea and progesterone hormone (P4) in blood the following time-points (2-weeks prepartum, 1-week prepartum, partum, 1-week postpartum, and 2-weeks postpartum). Both hypocalcemia- and ketosis affected buffaloes had lower glucose, phosphorus, sodium and albumin and higher NEFA than control group. Hypocalcemia-affected buffaloes showed lower calcium and higher total protein than control group, ketosis-affected buffaloes showed lower cholesterol and total protein than control group. Moreover, metabolic disorders negatively affected the reproductive performance. Both ketosis and hypocalcemia significantly prolonged the duration to first estrus, increased both the number of days-open and number of services per conception.