The randmomized control clinical trial has become the gold standard in scientific method for the evaluation of pharmaceuticals, biologics, devices, procedures, and diagnostic tests. This trial design has been successfully used in both therapeutic and disease prevention trials. It is superior to alternative designs by eliminating several sources of bias which exist in those designs. This role has evolved over the past three decades in a number of disease areas including cardiology, opthalmology, cancer and AIDS. While the specifics in using the randomized control design for a specific intervention and disease may differ, the basic fundamentals still apply in developing the study protocol and operational procedures. These fundamentals include identifying the specific questions to be tested and appropriate outcome measures, detailing the intervention with visit schedules for subject evaluation, establishing an an interim data and safety monitoring plan, detailing the final analysis plan, and determining the organizational structure.