Direct visualization of deep venous lesions with the ability to assess responses to treatment could present a major advance in venous interventions. A pilot in vivo feasibility study assessing use of a clinical endoscope for venous angioscopy was performed in a swine model. The angioscopy technique enabled visualization of the vein wall, of venous trauma and stenosis, and of response to stent placement. The interface of the stent and vein wall, including at the edge of treated segments, was visualized with high resolution. The experimental set up required control of blood flow and saline irrigation for adequate visualization. No immediate adverse events were observed in this acute, non-survival study.