Urea cycle disorders (UCDs) are a group of congenital genetic metabolic diseases with incidence of 1/46000-1/35000. Nonspecific clinical symptoms result from hyperammonaemia resulting in a high misdiagnosis rate, lethality and disability. An observational and retrospective analysis of the clinical features and outcome of children diagnosed with urea cycle disorders in our hospital in China was conducted (n=6;3 males & 3 females). The age of onset varied from neonate, 1+ months to 8 yrs. 5 children were misdiagnosed, suspected to have eaten high protein food or upper respiratory tract infection. 5 children had varying degrees of disturbance of consciousness, 4 children had seizures, 4 had vomiting and 2 had changes in their respiratory rhythm. An abnormal family history was present in three cases and the blood ammonia peak concentration fluctuated between 10-413umol/L during hospitalisation with four children showing impaired liver function. All 6 children showed abnormal blood tandem mass spectrometry and urine gas chromatography. Gene tests confirmed 4 cases of Ornithine Transcarbamase Deficiency (OTCD) and 1 case of carbamoyl phosphate synthetase I Deficiency (CPSID) and Citrin deficiency (CD) each. On follow up 1 patient died while two had cognitive decline. The clinical manifestations of UCDs are non-specific and easily misdiagnosed. Although determination of blood ammonia is the primary screening test, and blood tandem mass spectrometry and urinary organic acid gas chromatography are helpful, genetic diagnosis is still required for diagnosis and counselling. Early identification and correct treatment of UCDs are important for reducing mortality and improving prognosis.