Gene regulation by microRNAs (miRNAs) is one of the most important regulatory networks which control normal hematopoiesis. Disturbances in miRNAs levels lead to proliferation diseases including leukemogenesis. MicroRNAs is a major topic of many cancer researches performed to discover noninvasive biomarkers used for diagnosis, prognosis, and optimization of clinical decision. This study, the first to be performed in Syria, aimed at monitoring miR-155 levels compared to a normalizer gene RNU6-2 by quantitative reverse transcriptase -PCR (qRTPCR) in a sample of newly diagnosed untreated AML patients at several hospitals in Damascus in comparison with healthy controls. Changes in miR-155 gene expression levels were calculated in patients and controls using the 2-ΔCt method. The most important finding was the association of low and very high miR-155 levels with poor prognosis reflected in failure to accomplish complete remission and high mortality. In addition, high miR-155 levels were associated with M4 AML subtype, although with large variance among patients. We hope our preliminary study pave the road for many future research studies related to the applicability of microRNAs in supporting diagnosis, predicting prognosis, and enhancing the personalized therapies which deal with patients as individual cases.