Catheter-induced subclavian and internal jugular vein thrombosis in a patient with unresectable ovarian carcinoma was diagnosed by sonography following subtle clinical symptomatology. Ultrasonographic diagnosis of central vein thrombosis offers applicable, noninvasive bedside diagnosis. The case we describe suggests that a low threshold should be maintained for application of this technique in the diagnosis of this potentially life-threatening complication, especially with the current widespread application of invasive monitoring.