The guideline was drafted by a writing group identified by the Haemostasis and Thrombosis Task Force of the British Committee for Standards in Haematology (BCSH). All the authors are consultants in haematology in the UK. A search was performed of PubMed and Embase using the term 'cancer' combined with 'thrombosis', 'treatment', 'prophylaxis' and 'clinical presentation'. The search covered articles published up until December 2014. Only human studies were included and articles not written in English were excluded. References in recent reviews were also examined. The writing group produced the draft guideline, which was subsequently revised by consensus by members of the Haemostasis and Thrombosis Task Force of the BCSH and the BCSH executive. The guideline was then reviewed by the sounding board of the British Society for Haematology (BSH). This comprises 50 or more members of the BSH who have reviewed the guidance and commented on the content and application to the UK setting. The 'GRADE' system was used to quote levels and grades of evidence, details of which can be found at: http://www.bcshguidelines.com/BCSH_PROCESS/EVIDENCE_LEVELS_AND_GRADES_OF_RECOMMENDATION/43_GRADE.html. The objective of this guideline is to provide healthcare professionals with clear guidance on the prevention and management of venous thromboembolism (VTE) in patients with cancer and to advise on an approach to screening for cancer in patients with unprovoked VTE in whom cancer was not initially suspected based on clinical grounds.(AU)