The hematological effects of khat chewing, a widespread habit in East Africa and Yemen, remain inadequately characterized, particularly regarding coagulation. Similarly, evidence linking sleep duration to hematological markers in young, healthy populations is limited. In a cross-sectional study of 600 Yemeni university students, we assessed khat chewing frequency, sleep duration. Prothrombin time (PT), activated partial thromboplastin time (APTT), and complete blood count were measured. Multivariate logistic regression models adjusted for age, gender, and BMI. Weekly khat chewers had significantly higher odds of abnormal PT (aOR = 2.31, 95% CI: 1.05–5.08, p=0.037) and abnormal APTT (aOR = 3.78, 95% CI: 1.55–9.22, p=0.003) compared to never-users. A non-linear dose-response was observed, with weekly users showing the most pronounced coagulation abnormalities. Participants reporting long sleep duration (>8 hours) had over four times the odds of abnormal platelet counts (aOR = 4.12, 95% CI: 1.62--10.49, p=0.003) compared to the reference group (7-8 hours). Khat chewing is independently associated with significant coagulation abnormalities, suggesting potential interference with both intrinsic and extrinsic pathways. Furthermore, long sleep duration is a novel predictor of platelet count disturbances in this young cohort. These findings highlight potential public health risks, calling for greater clinical awareness of the hematological sequelae of khat use and suboptimal sleep patterns in this population.