Objectives:To study the effects of heavy cigarette smoking on coagulation (CGG) screening tests and platelet counts (PLTs) in a Sudanese male adults population.Methods:A case control study was conducted at both Kosti and Gabalein towns, Sudan, during October 2016 to May 2017. A 100 adult cigarette smokers were selected and another 100 matched non-smokers were selected as healthy controls. Blood samples were collected in trisodium citrate anti-coagulant for prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR), analyzed using standard methods (co-agulometer machine) and Ethylenediaminetetraacetic acid for the platelet counts, using an automated haematology analyzer (Sysmex, Tokoyo, Japan).Results:The results showed that the mean platelet counts were significantly lower in the smokers (183x103/cmm±64x103/cmm) versus (244x103/cmm±38x103/cmm) in non-smokers, (p<0.000). Pearson correlation analysis suggested a weak negative correlation between platelet counts with the duration of smoking (r= -0.289, p<0.004) and the age of the smokers (r= -0.238, p<0.017). The mean PT and INR were also significantly lower in smokers (12.9±1.2 seconds) compared with the non-smokers (13.7±1.04 seconds, p<0.000), for PT and (0.95±0.09 versus 1.01±0.08, p<0.000) for INR. In contrast, PTT had no significant variation in smokers (30.5±3.8 seconds) and the non-smokers (37.9±4.6 seconds). A p-value>0.05 was considered significant.Conclusion:Cigarette smokers tend to have lower platelet counts, shorter PT, and INR values, compared to non-smokers. Therefore, smoking might be associated with bleeding disorders but further investigations are needed.