The pathophysiology of calf perforators is presented. Bidirectional flow within calf perforators with a prevailing inward, into deep veins oriented component arises during calf pump activity in varicose vein patients, as evidenced by venous pressure measurements, plethysmographic findings, duplex ultrasonography, and electromagnetic flow measurements. Reflux within calf perforators is an inward, not outward, flow; the opinion that the outward flow within calf perforators is a reflux is at odds with the reality. During calf muscle contraction, the pressure in the posterior tibial vein is higher than in the great saphenous vein; it induces the harmless outward flow within calf perforators, which runs further via great saphenous vein in the physiological direction toward the heart. Deep and superficial veins of the lower leg form conjoined vessels, as documented by nearly equal pressure curves registered simultaneously in the posterior tibial and great saphenous veins both in varicose vein patients and in healthy people. Calf perforators do not entail ambulatory venous hypertension or any other hemodynamic disorder, even if enlarged and incompetent; their ligation is needless. The diameter of calf perforators is influenced by the intensity of saphenous reflux; it enlarges with increasing intensity of saphenous reflux and diminishes after the abolition of reflux.