Background: Activated Phospho-Inositide 3 (PI3) Kinases Delta syndrome (APDS) can underlie primary immune deficiency. The prevalence and phenotypic characterization of these patients are not well described in Egypt. Objectives: To describe patients with APDS in hospitalized children with recurrent respiratory tract infections with suspected primary immune deficiency. Methods: 79 patients were included in the study. E1021K and E525K mutations of PI3K chain gene were screened by Sanger sequencing technique. Results: one patient was heterozygous to E1021K mutation; a female child was diagnosed clinically as Combined Immune Deficiency with CD4 and B lymphopenia and markedly deficient Ig G and increased IgM. The E525K mutation was not detected in our cohort. Conclusions: Screening for APDS in patients with recurrent respiratory tract infections with undefined antibody deficiency or combined immune deficiency with or without bronchiectasis is required. These patients need great attention to benefit from the available treatment. Further studies on the Egyptian population are recommended to increase the knowledge about the prevalence and phenotypic characterization of this disease in Egypt.