Catheter-related thrombosis (CRT) is a relatively frequent and potentially fatal complication arising in patients with cancer who require a central catheter placement for intravenous treatment. In everyday practice, CRT remains a challenge for management; despite its frequency and its negative clinical impact, few data are available concerning diagnosis and treatment of CRT. In particular, no diagnostic studies or clinical trials have been published that included exclusively patients with cancer and a central venous catheter (CVC). For this reason, many questions regarding optimal management of CRT remain unanswered. Due to the paucity of high-grade evidence regarding CRT in cancer patients, guidelines are derived from upper extremity DVT studies for diagnosis, and from those for lower limb DVT for treatment. This article addresses the issues of diagnosis and management of CRT through a review of the available literature and makes a number of proposals based on the available evidence. In symptomatic patients, venous ultrasound is the most appropriate choice for first-line diagnostic imaging of CRT because it is noninvasive, and its diagnostic performance is high (which is not the case in asymptomatic patients). In the absence of direct comparative clinical trials, we suggest treating patients with CRT with a therapeutic dose of either a LMWH or a direct oral factor Xa inhibitor, with or without a loading dose. These anticoagulants should be given for a total of at least three months, including at least one month after catheter removal following initiation of therapy.