Patients with brain tumors may suffer from cognitive deficits caused by the disease and/or its treatment. Here, we review recent efforts in the research on prevention or treatment of cognitive deficits in these patients. We conclude that interest in this area is growing, but that methodological difficulties persist. In addition, we describe the recently completed first randomized controlled trial on the effectiveness of cognitive rehabilitation that we conducted in patients with brain cancer. By reflecting on the methodological challenges experienced in our trial, we hope to assist others in planning and conducting future studies on both pharmacological treatments and cognitive rehabilitation programs for cognitive deficits in this patient population. We conclude with suggestions for future research directions.