Background: Age and sex, obesity >30 Kg/m2 increased the risk of thrombosis two-fold. The present study was conducted to assess the factors playing role in development and outcome of venous system thrombosis. Materials& Methods: A prospective observational cohort study design was adopted to assess the factors playing role in development and outcome of venous system thrombosis. The study was conducted among 100 patients. Various invasive and noninvasive radiological investigations and hematological investigations were done. Results: Of total 30 patients of CVST, 20 patients presented with headache and 10 patients had no headache which shows that 66% patients had headache. Out of 43 females, 55% cases were pregnant or in puerperium which was observed as major risk factor for development of venous thrombosis at various anatomical sites. Also, maximum patients had CVST as most common site of thrombosis in pregnancy and puerperium. In our study headache was most common symptom of CVT followed by nausea and vomiting. In DVT swelling and pain over affected limb was the most common symptom as it was observed in 49 among the 50 patients. For PVT pain abdomen and blood in vomitus and/or stool was most common symptom. Chest pain was observed in 11 patients of which 6 had DVT+PTE 2 had PTE and SVT and rest 1 patient had subclavian vein thrombosis. Among male patients, major risk factors for venous thrombosis is diabetes mellitus and smoking. Conclusion: The present study concluded that of a total of 30 patients of CVST, 20 patients were presented with headache. Out of 43 females, 55% cases were pregnant or in puerperium which was observed as major risk factor for development of venous thrombosis at various anatomical sites. Among male patients, major risk factors for venous thrombosis are diabetes mellitus and smoking.