Venous thromboembolism (VTE) has an incidence between 0.7 and 2.69 per 1000 per year. Temporary lower limb immobilisation after an injury is a significant contributor to Deep venous thrombosis (DVT). Previous studies showed an incidence rate between 1% to 20%. However, the real incidence of DVT in patients with isolated stable ankle, foot fractures and sprains treated conservatively is not well known. Objectives: This study aims to assess the incidence of VTE after lower limb plaster immobilisation and if we should consider giving chemoprophylaxis. Patients and methods: A prospective cross-sectional study included consecutive twenty patients with stable ankle, foot fractures, and sprains managed conservatively with below-knee plasters. There was no national/local policy to offer VTE prophylaxis. VTE Risk assessments were done and documented. After Plaster removal, all patients had a Doppler ultrasound examination (DUE) to confirm or rule out VTE diagnosis. Results: Twenty patients (11men/ 12women) were followed up for at least six weeks. The Mean age was 46.30±17.50 (Range 18-70) years old. Twelve patients had below-knee cast (60%), Eight had below knee slab (40%). The mean immobilisation duration was 38.50±15.8 (Range 15-62). Thirteen patients (65%) had an increased risk for VTE.  One patient (5%), 28 years female, had DVT, scoring only one point of VTE risks (oral contraceptive pills). She was a non-smoker with, BMI of 26. She was diagnosed with a popliteal DVT after removing a below-knee slab for ankle sprain at two weeks post-injury and treated accordingly with no complication. Conclusion: Incidence of DVT after below-knee cast immobilisation about 5%. Similar patients should be assessed, and proper prophylaxis is given to decrease the morbidity and mortality of having VTE