One thousand patients referred to genetics clinic, Medical Research Institute, Alexandria, were subjected to biochemical genetic studies and clinical genetic examination to estimate the frequency of inborn errors of metabolism [IEM]. It was found that 70 [7%] patients had IEM. Of these, 34 [48.6%] had aminoacidopathies, 3 [4.3%] had galactosemia, and 33 [47.1%] had lysosomal storage disorders. Phenylketonuria was the most frequent IEM [37.2%]. The rate of consanguinity among parents of patients with IEM was high [77.1%] with 58.6% first cousins. Positive family history of more than one affected child was detected in 22 [31.4%] families of the patients with IEM. Detection of IEM is important because it may allow a specific treatment for the patients and Proper genetic counseling for the family.