Background:The golden ratio (GR), also known as phi (φ: 1.618), is a harmonic ratio found throughout nature.Objective: We seek to correlate the GR with the venous diameters of the deep venous system of the lower extremity (LE).Material and methods: We performed a case series study with a sample of 43 healthy volunteers, between September and December 2020, comparing the diameters of the common femoral vein (CFV) 5-10 cm distal to the inguinal ligament and the popliteal vein (POPV) using the formula (CFV/CFV + VPOP).Results: The mean of the calculations for the right LE was 0.61 cm (99% CI: 0.59-0.62)and for the left LE was 0.59 cm (99% CI: 0.57-0.60).Conclusions: Venous diameter ratios were descriptively close to 1/φ.This is the first study on the role of phi in the venous circulation.Its application could contribute to real-life use in the field of innovation in vascular surgery.