Klippel-Trenaunay syndrome (KTS) is a rare disorder that consists of a triad of capillary vascular malformation, venous malformations and/or varicose veins, and soft tissue and/or bony hypertrophy. Pain is a real and debilitating problem in these patients. We have observed 9 common causes of pain in KTS: (1) chronic venous insufficiency, (2) cellulitis, (3) superficial thrombophlebitis, (4) deep vein thrombosis, (5) calcification of vascular malformations, (6) growing pains, (7) intraosseous vascular malformation, (8) arthritis, and (9) neuropathic pain. The management of pain in patients with KTS depends on its cause. These patients are best evaluated initially in a center with an experienced multidisciplinary team that includes a primary health care provider, surgeons, and ancillary staff. The ongoing care of a patient with KTS often depends on a local provider who is more readily accessible to the patient but may not have the expertise of a large center to manage the complications of KTS. The purpose of this communication is to review the common causes of pain in these patients to provide local health care providers and patients and their families with appropriate management strategies.