Background: Venous thromboembolism (VTE) is a serious and fatal disease, that can significantly impair the recovery of the hospitalized patients. The aim of this study was to determine the prevalence rate, beside identifying the most common risk factors that associated with VTE among critically ill and hospitalized patients at King Khalid hospital in Najran. Materials and methods: It was a cross sectional study that conducted during the period from October, 2017 up to February, 2018. 194 patients were chosen randomly from 4 areas in the hospital. A questionnaire as a tool was used to collect personal data, while the rest of the information were obtained from the patients' records as well as from the health personnel. Results: The participants' mean age was 35 ±13.6 years old for those with VTE, while the mean age for those without VTE was 33± 14.1 respectively. The majority of patients were above 40 years old, among them 54.6% were male. The results show that most of the studied subjects 156 (80.4%) were hospitalized for various medical illness, while the rest 38(19.6%) had undergone surgery respectively. Moreover, 37.1% of the respondents had been hospitalized for more than four weeks. The overall VTE prevalence was 3.1%. Multiple risk factors had been identified to be associated significantly with VTE. These factors including advanced age that over 40 years old (OR 1.04; CI 0.39 – 2.08), stroke (OR 0.56; CI 0.71-1.53 and P-value 0.04), Renal diseases and on dialysis (OR 0.55; CI 0.63-1.04 and P-value 0.001), Positive personal or family history of VTE (OR 0.81; CI 0.76-2.01 and P-value 0.001), Immobility (OR 1.11; CI 1.16-2.07 and P-value 0.02), as well as malignancy (OR 0.92; CI 1.47-2.35 and P-value 0.03). Patients with renal problems showed the highest prevalence rate in relation to other medical problems among the studied sample (27.8%). Most of respondents (57.7%) had either personal or family history of PE, DVT or both. The findings of the current study show that males have higher prevalence of VTE (2.1%) than females(1%) with (OR 1.89 and CI 0.48- 2.01), while for men (OR 2.06; CI 0.51- 1.99) respectively. On the other hand, sex, length of hospital stay, Diabetes M., hypertension, congestive heart failure, wounds' infection, mechanical ventilation and central vein catheterization were not significantly associated with VTE. Conclusion and recommendation: It was concluded that critically ill patients have an increased risk of developing VTE due to multiple factors. Therefore, adherence to clinical practice guidelines for VTE prophylaxis could have contributed to lower the incidence rate.