P53 as a tumor suppressor gene plays a major role in cancer development, it is essential for cell growth regulation and apoptosis. The deletion of p53 is known to be associated with aggressive diseases in several hematological malignancies. The evidence indicated that p53 deletions can be acquired as a result of chemotherapy. Therefore, a follow-up study for p53 gene deletion by fluorescence in situ hybridization technique (FISH) was carried out for the patients group who affected with different hematological malignancies before and after chemotherapy. The main goals from screening of p53 deletion were to assess the correlation between p53 deletion and chemotherapy resistance, overall median survival and chromosomal abnormalities. It is concluded from the present study that p53 deletion has a cardinal effect on the clinical outcome (chemotherapy resistance, overall median survival) and outcome of chromosomal abnormalities (quality and quantity of chromosomal abnormalities) of the patients who were affected with hematological malignancies before and after chemotherapy.