Objective: To identify the most prevalent diseases of transition period in dairy cows and to highlight potential risk factors that are supposed to play a critical role in the prevalence of hypocalcaemia. Design: Case-control study Animals: 179 transition dairy cows belonged to five farms. Procedures: In the selected dairy cows, both clinical examination and serum analysis were used as a key to diagnose the transition period disorders. The serum analytes were measured, including calcium (Ca), inorganic phosphorous (P), magnesium (Mg), parathyroid hormone (PTH), glucose, potassium (K), sodium (Na) and chloride (Cl) and then their cutoff points were set. A questionnaire was constructed to identify the possible risk factors associated with hypocalcaemia on both the farm and cow level. Results: In this study, the prevalence of hypocalcaemia, hypophosphatemia, hypomag-nesaemia, hypoglycemia, hypokalemia, clinical ketosis, and abomasal displacement was 48.04%, 40.22%, 33.52%, 29.05%, 58.1%, 5.59%, and 1.12%, respectively. Furthermore, the prevalence of post parturient septic metritis, retained placenta, and clinical mastitis was 26.81%, 23.46%, 18.99%, respectively. On farm level, the type of the diet, housing criteria, and periodical monitoring of metabolic profile test significantly (P < 0.05) affected the incidence of hypocalcaemia. On cow level, age, parity, body condition score, stage of transition period, daily milk yield, and history of presence of previous transition period disorders had a significant (P < 0.05) effect on the occurrence of hypocalcaemia. Moreover, the occurrence of hypocalcaemia in the studied dairy cows was significantly correlated with high level of each of PTH (P = 0.006), glucose (P = 0.001), K (P = 0.019), Na (P = 0.001), and Cl (P = 0.045). Conclusion and clinical relevance: The results of the current study pointed the importance of regular monitoring of the transition period disorders in dairy cows, besides the identification of the potential risks and consequences of hypocalcaemia in an attempt to establish control measures for them, which in turn will increase the profitability of dairy herds.