Background: Around the world, Hepatitis C (HCV) is the primary cause of liver disease. HCV infection in absence of a positive HCV test (Occult hepatitis C) is a significant clinical and epidemiological issue, although the pathogenic mechanisms behind this illness are not well comprehended. Objective: This study aimed at investigation of seronegative and occult hepatitis C virus among patient with acute and chronic myeloid leukemia. Patients and methods: 85 leukemic patients were studied in the current cross-sectional trial. In accordance with the kind of myeloid leukaemia (ML), patients were divided into 72 patients with acute ML (AML group) and 13 patients with chronic ML (CML group). And according to the presence of occult HCV infections, they were divided into 12 patients (14.1%) with negative serum HCV Abs and positive serum HCV RNA (seronegative), while the other 73 (85.9%) were free of HCV RNA in their bloodstreams. Results: Patients with occult HCV infections had significantly higher monocytic count and significantly lower platelet count. Also, they had significantly lower total plasma protein and serum creatinine levels compared to those in the seronegative group. Patients with CML had either normal platelet count or even thrombocytosis, while those with AML showed thrombocytopenia with a statistical significant difference. Patients with AML had significantly higher AST. Conclusions: Seronegative and occult HCV are significant clinical problems in leukemic patients and needed to be more and more evaluated.