Objective: Few studies have investigated outcomes after truncal endovenous ablation in patients with combined deep and superficial reflux and no studies have evaluated patient-reported outcomes. Methods: We investigated the short- and long-term clinical and patient-reported outcomes among patients with and without deep venous reflux undergoing truncal endovenous ablation from 2015 to 2019 in the Vascular Quality Initiative. Preprocedural and postprocedural comparisons were performed using the t-test, χ2, or their nonparametric counterpart when appropriate. Multivariable logistic regression models were used to assess for confounding. Results: A total of 4881 patients were included, of which 2254 (46.2%) had combined deep and superficial reflux. The median follow-up was 336.5 days. Patients with deep reflux were less likely to be female (65.9% vs 69.9%; P =.003), more likely to be Caucasian (90.2% vs 86.5%; P =.003) and had no difference in BMI (30.6 ± 7.5 vs 30.6 ± 7.2; P =.904). Additionally, no difference was seen in rates of prior varicose vein treatments, number of pregnancies, or history of deep venous thrombosis; however, patients without deep reflux were more likely to be on anticoagulation at the time of the procedure (10.9% vs 8.1%; P <.001). Patients without deep reflux had slightly higher median preprocedural Venous Clinical Severity Score (VCSS) scores (8 [interquartile range (IQR), 6-10]) vs 7 [IQR, 6-10]; P =.005) as well as postprocedural VCSS scores (5 [IQR, 3-7] vs 4 [IQR, 2-6]; P <.001). The median change in VCSS from before to after the procedure was lower for patients without deep reflux (3 [IQR, 1.0-5.5] vs 3.5 [IQR, 1-6]; P =.006). Total symptom score was higher for patients without deep reflux both before (median, 14 [IQR, 10-19] vs median, 13.5 [IQR, 9.5-18]; P =.005) and postprocedurally (median, 4 [IQR, 1-9] vs median, 3.25 [IQR, 1-7]; P <.001), but no difference was seen in change in symptom score (median, 8 [IQR, 4-13] vs median, 9 [IQR, 4-13]; P =.172). Patients with deep reflux had substantially higher rates of complications (10.4% vs 3.0%; P <.001), with a particular increase in proximal thrombus extension (3.1% vs 1.1%; P <.001). After controlling for confounding, this estimate of effect size for any complication increased (odds ratio, 5.72; 95% confidence interval, 2.21-14.81; P <.001). Conclusions: No significant difference is seen in total symptom improvement when patients undergo truncal endovenous ablation with concomitant deep venous reflux, although a greater improvement was seen in VCSS score in these patients. Patients with deep venous reflux had a significantly increased rate of complications, independent of confounding variables, and should be counseled appropriately before the decision for treatment.