Bone marrow transplantation is one of the most intensive forms of cancer treatment, involving a prolonged period of recovery and rehabilitation. This project gave me a unique opportunity to work with Sloan-Kettering to design improvements to the rehabilitation phase following a bone marrow transplant. The research phase of this project lasted six weeks and included background reading, observation exercises at MSKCC, photography, and 1:1 interviews with doctors, nurses, therapists, patients and administrators. The key finding of this research was the importance of physical activity to patients’ physical and mental wellbeing. Using a commercially available, networked pedometer, FitBit, I developed a web and mobile service to help patients set goals and receive feedback on their level of physical activity. The service gives medical staff access to a dashboard showing patients’ physical activity, allowing them to offer encouragement and make better clinical decisions. The service, called MSKCC Activity App, has now been written into a forthcoming clinical trial, allowing it to be tested with MSKCC patients.