Background: Thromboprophylaxis of ambulatory cancer patients is considered controversial. However, some guidelines suggest conducting VTE risk assessment using the Khorana risk assessment scoring model. This study aims to assess the incidence of Deep Vein Thrombosis (DVT) and related cancer types, focusing on the incidence of DVT in ambulatory patients actively on chemotherapy, with Khorana risk score (KRS). Methods: The Doppler ultrasound reports over 12-month period were reviewed. A total of 205 patients were included in the study. Patients with DVT were screened for the relevant biomarkers in KRS model and any other additional risk factors. Furthermore, a comparison between ambulatory patients who developed DVT and those who did not, was carried on determining the KRS association with incidence. Results: The incidence of DVT in ambulatory cancer patients was higher than the inpatient setting (23% vs. 8%). Breast cancer was the most common malignancy associated with DVT (30%) followed by colon cancer (17%). Chemotherapy increased the incidence of DVT in ambulatory patients (29% vs. 13%). Patients with KRS of ≥2 were more likely to develop DVT (37.5%). Conclusion: This study highlights the importance of conducting a thorough DVT risk assessment for ambulatory cancer patients on chemotherapy and the need to look for KRS to reconsider additional risk factors.