It is difficult for practicing physicians to understand the annual incidence of disease in terms that are directly relevant to their practices. A simple calculation, called the family practice incidence rate (FPIR), has been developed to assist family physicians in applying epidemiological information to their own patient population.By multiplying the annual incidence of a disease by the practice panel size and dividing by the population, it is possible to determine the number of cases a family physician will see in 1 year. When the answer is a fraction, that fraction can be divided into 1 year to determine the number of years required to encounter one case. This formula can be adjusted for panel size, specific percentages of the practice panel and regional variations in incidence rates.The FPIR is a convenient model to make the incidence of disease, mortality data, and demographic data immediately available to the practicing physician. Using this calculation will help physicians better understand the patient population they serve.