Superficial venous thrombosis (SVT) prognosis is debated and its management is highly variable. It was the objective of this study to assess predictive risk factors for concurrent deep-vein thrombosis (DVT) at presentation and for three-month adverse outcome. Using data from the prospective multicentre OPTIMEV study, we analysed SVT predictive factors associated with concurrent DVT and three-month adverse outcome. Out of 788 SVT included, 227 (28.8%) exhibited a concurrent DVT at presentation. Age >75years (odds ratio [OR]=2.9 [1.5–5.9]), active cancer (OR=2.6 [1.3–5.2]), inpatient status (OR=2.3 [1.2–4.4]) and SVT on non-varicose veins (OR=1.8 [1.1–2.7]) were significantly and independently associated with an increased risk of concurrent DVT. 39.4% of SVT on non-varicose veins presented a concurrent DVT. However, varicose vein status did not influence the three-month prognosis as rates of death, symptomatic venous thromboembolic (VTE) recurrence and major bleeding were equivalent in both non-varicose and varicose SVTs (1.4% vs. 1.1%; 3.4% vs. 2.8%; 0.7% vs. 0.3%). Only male gender (OR=3.5 [1.1–11.3]) and inpatient status (OR=4.5 [1.3–15.3]) were independent predictive factors for symptomatic VTE recurrence but the number of events was low (n=15, 3.0%). Three-month numbers of deaths (n=6, 1.2%) and of major bleedings (n=2, 0.4%) were even lower, precluding any relevant interpretation. In conclusion, SVT on non-varicose veins and some classical risk factors for DVT were predictive factors for concurrent DVT at presentation. As SVT remains mostly a clinical diagnosis, these data may help selecting patients deserving an ultrasound examination or needing anticoagulation while waiting for diagnostic tests. Larger studies are needed to evaluate predictive factors for adverse outcome.