BACKGROUND Cytogenetic abnormalities have important implications in diagnosis and prognosis of acute leukemia and are now considered an important part of the diagnostic workup at presentation. Karyotype, if known at the time of diagnosis, guides physicians to plan appropriate management strategies for their patients. OBJECTIVE To determine the cytogenetic profile of acute lymphoblastic leukemia (ALL) in Pakistani children in order to have insights regarding behavior of the disease. METHODS A retrospective analysis of all the cases of ALL (<15years old) diagnosed at Aga Khan University from January 2006 to June 2011 was performed. Cytogenetic analysis was made for all cases using the trypsin-Giemsa banding technique. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature (ISCN) criteria. RESULTS A total of 153 patients were diagnosed as ALL during the study period, of which 127 samples successfully yielded metaphase chromosomes. The male to female ratio was 1.8:1. A normal karyotype was present in 51.2% (n=65) of the cases whereas 48.8% (n=62) had an abnormal karyotype. Most of the abnormal cases showed hyperdiploidy(13.4%) followed by t(9;22)(q34;q11.2) (7.08%). CONCLUSIONS This study revealed a relative lack of good prognostic cytogenetic aberrations in Pakistani children with ALL.