Inclusion Criteria:  Presence of fatigue on a numerical scale during the last 24 hours of more or equal to 4 on a 0 to 10 scale in which 0 equals no fatigue and 10 worst possible fatigue. Patients should describe fatigue as being present for a minimum of four days. If patients are on opioids for the treatment of cancer pain, change of opioids is allowed. No clinical evidence of cognitive failure, with normal Mini Mental State Examination (MMSE). A score of 24 is considered as normal. Sign written informed consent. Patients must be 18 years or older. Patient willing to keep a daily diary, engage in daily telephone follow up with a nurse, and after 7 days of treatment patient will return for a follow up visit. Patient must have telephone access to be contacted daily by the research nurse. Hemoglobin of >/=10 g/dl within 2 weeks of enrollment. If the patient has not had blood drawn for a hemoglobin level in the past two weeks, one will be done to determine the eligibility.  Exclusion Criteria:  Major contraindication to methylphenidate i.e. hypersensitivity, anxiety, tension, agitation, or motor tics Currently on methylphenidate or has been on methylphenidate within the last 10 days. Inability to complete the baseline assessment forms or to understand the recommendations for participation in the study. Pregnant or lactating women. Patients taking MAO inhibitors, tricyclic antidepressants and clonidine. Patients with glaucoma, history of marked anxiety disorder, or history of substance abuse. CAGE questionnaire score for the last 2 years is 2 or above on a 0 to 4 scale History of Tourette's syndrome Patients with tachycardia and uncontrolled hypertension.