Introduction: Gestational diabetes mellitus occurs in 2-9% of all pregnancies, and is associated with substantial rates of maternal and perinatal complications. Although the risks associated with gestational diabetes are well recognized, it remains uncertain whether screening and treatment to reduce maternal glucose levels reduce these risks. Aim: We aim to study the characteristic of diabetic pregnant patients admitted and managed at Kasr El-Ainy Maternity Hospital in the period from 2005 - 2009. Subject and Methods: The study included 137 pregnant diabetic females. Laboratory investigations included FBs, PPs, and other tests. We assessed the number of Gestational and Pre Gestational cases, the characteristic of each group (with Gestational or Pre Gestational) regarding maternal age, parity, obstetric and medical complication, insulin dose, mode of delivery and neonatal weight where also determined.Results: 71.5% of the study population where below 35 years and 28.4% were above 35 years. No significant difference noted between the Gestational age in on admission of both groups.No significant different were noted regarding maternal age, parity, obstetric and medical complication ,insulin dose ,mode of delivery and neonatal weight between the Gestational and Pre Gestational diabetic pregnant patients.Mean FBS & 2h PPBS were significantly higher in Pre Gestational diabetic patients.Conclusion and recommendation : The number of Gestational Diabetic cases is rising compare to the number of per existing diabetic pregnant cases.Where the Gestational diabetic cases are more controlled regarding Blood sugar levels .Where Better documentation is need to extracted other reliable conclusion.