Cancer related fatigue (CRF) is the most debilitating problem for patients with haematological cancer. CRF severely reduces quality of life (QoL), functional capacity, impacts health behavior, recovery and furthermore no approved treatment exists. In solid cancer methylphenidat (MTP) has been suggested to improve CRF, however patients with haematological cancer has not been studied. The current randomized placebo controlled study includes a variety of severely fatigued haematological cancer patients from seven Danish departments. It aims at revealing whether MTP can improve CRF, functional capacity and QoL thereby hopefully providing improvement and treatment options in this field where improvements are requested the most by patients. Patients are randomized to treatment with MTP or placebo week 1-6 followed by "wash-out" and cross-over - placebo to MTP or vice versa - during week 8-13. End-points will be patient reported fatigue, as well as improvements in active hours, functional capacity, and QoL.