Background: sP-selectin is a marker for atherosclerosis and inflammation. It provides prognostic information on cardiovascular events, as reported in the literature. The aim of the present study was to evaluate sP-selectin as a biomarker for cardiovascular mortality in an elderly primary healthcare population, with a focus on possible sex differences Objective: To evaluate role of P-selectin as a marker of platelets activation in coronary slow flow patients. patients: A case control study, where seventy two patients underwent cardiac catheterization for suspected coronary artery disease. There were divided into patients group (primary coronary slow flow patients) and controlgroup(normalcoronaryangiography) . Methods:All patients were subjected to history ,physical examination and laboratort investigation included CBC serum glucose,lipid profile and immunophenotyping of platelets activation(p selectin CD 62p by flowcytometery). Results: We have two groups: Group1 (patients group): Patients with primary coronary slow flow phenomenon = 36 patients. Mean age of cases 49.33±4.99 years with range of (34-55) years .In patients group there was 24 male and 12 female. Group II (control group): Patients with normal coronary angiography = 36 patients. Mean age in control group 51.44±3.36 years with range of (43-55) years. Conclusion: The results of the present study revealed that there is very high statistically significant difference in P-selectin level between group 1 (primary coronary slow flow patients) and group 2 (normal coronary angio patients) and there is statistically significant association between P-selectin and TIMI frame count in coronary slow flow.