Intensified treatments with multi-drug regimens are responsible for the continuously increasing survival of children with acute lymphoblastic leukaemia. However, together with the widespread use of central venous lines, they are also considered the main risk factors for the growing number of thromboembolic complications in this population. The rate of thrombosis that was observed in 17 prospective studies was 5.2%. Due to the high survival rate, it is relevant to apply strategies to the long term survivors who overcome the disease but who experience thromboembolic complications. Specific treatment includes anticoagulants, especially unfractionated heparin and low molecular weight heparins, and thrombolytic drugs in few cases. Guidelines for the treatment of thrombosis in childhood only became available recently, but they do not include specific clinical subsets such as children with acute lymphoblastic leukaemia. The problems involved in scheduling thrombosis treatment in children with malignancy have recently been discussed, however the paper does not provide practical diagnostic schemes or treatment schedules. Some important questions regarding optimal prevention and treatment are still unanswered. Moreover, antithrombotic therapy in these patients is quite challenging owing to the higher risk of bleeding. We believe it would be possible to propose reasoned appropriate recommendations for treating thrombosis in children with acute lymphoblastic leukaemia, looking forward for the effects of recent patents. This paper is an attempt to provide a practical guide to the diagnosis and treatment of thrombotic events in children with acute lymphoblastic leukaemia, and it is aimed at physicians who have no specific knowledge of the diagnosis and management of thrombosis and haemostasis alterations in children.