Objectives: The greater saphenous vein (GSV) is commonly used in autologous vein graft surgery. GSV diameter has proven to influence graft patency, and furthermore venous compliance might be of importance. The purpose of the study was to evaluate the effect of age on GSV diameter and compliance, and to evaluate the effect of nitroglycerine (NTG). Methods: The diameter and compliance of the GSV, with and without NTG, were examined with B-mode ultrasound in 12 elderly (70.3 +/- 1.2 year) and 15 young (25.1 +/- 0.6 year) men. The GSV diameter at the thigh and calf level was measured at rest, after 6 min of venous stasis (60 mmHg) and after NTG administration. Pressure-area curves during a linear venous pressure decrease were produced. Venous compliance was calculated using the quadratic regression equation (area) = beta(0) + beta(1) (cuff pressure) + beta(2) (cuff pressure)(2). Results: GVS diameter between the groups showed significant lower diameter in elderly compared to young men (Pless than0.05). Venous occlusion increased GSV diameter in elderly men (Pless than0.01) as well as young men (Pless than0.001). NTG increased GSV diameter in elderly men (Pless than0.01) with an equal trend in young men. During venous occlusion, after administration of NTG, GSV diameter increased further in both elderly (Pless than0.01) and young men (Pless than0.001). GSV compliance was decreased in elderly (beta(1), 0.037 +/- 0019, beta(2), -0.000064 +/- 00017) versus young men (beta(1), 0.128 +/- 0.013, beta(2), -0.00010 +/- 000018) [Pless than0.001 (beta(1)), Pless than0.02 (beta(2))]. Conclusions: Baseline GSV diameter as well as GSV compliance is decreased in elderly men compared to the young subjects. As reduced GSV diameter as well as reduced compliance is related to decreased graft patency, these findings might be of importance for the uses of GSV as graft material in cardiovascular bypass surgery. The clinical value has to be clarified in future studies.