Introduction: Nucleophosmin1 (NPM1) gene mutation is the most frequently occurring gene mutation in acute myeloid leukemia. This mutation is associated with good prognosis. AML patients should be screened for the NPM1 gene mutation to identify patients with good response to chemotherapy. Its association with FLT3-ITD mutation is related to poor outcome. B: To evaluate the frequency of NPM1 gene mutation in newly diagnosed patients of AML. Study design: Cross sectional study. Settings and duration: Armed Forces Institute of Pathology (AFIP), Rawalpindi from 1st September 2014 to 30th June 2015. Patients and duration: Patients of age between 5 to 85years and both gender diagnosed with AML at AFIP were included. After informed consent 2ml bone marrow samples were collected from patients. RNA was extracted and complimentary DNA was synthesized using reverse transcriptase. Polymerase chain reaction (PCR) was done using Amplification refractory mutation system methodology. PCR products were visualized by electrophoresis on Poly Acryl Amide Gel. Results: Out of 95 AML patients34 (35.7%) were positive for NPM1 gene mutation with a median age of 47years. 80 were males while 15 were females. Out of 34 NPM1 positive patients 14 (26.9%) were AML M2 subtype, 13 patients (38.2%) were AML M4 , 03 (8.82%) were AML 3 while there were 4(11.7%) cases of AML M5. Conclusion: NPM1 gene mutation is quite frequent in our patients of AML and its identification will help identify patients with good response to chemotherapy.