The clinical trial sponsor (such as a government organization, pharmaceutical company, or other non profit organization) may pay for all or a portion of the experimental treatments, special testing, extra doctor visits, travel time, and travel expenses that come along with participation in the trial.

Some health insurance companies will cover the costs of procedures that patients would have even if they were not in a clinical trial (routine costs).  For Medicare patients, routine costs are covered in all Medicare-qualified clinical trials. 

You will be responsible for any costs not covered by the clinical trial sponsor or your health insurance company.  Therefore, be sure to ask the principle investigator or research nurse specifically about what costs will be your responsibility if you decide to participate in a clinical trial. 

CancerCare's Tips for Finding Financial Assistance