Census figures point out the increase in the population of stepfamilies, families in which one adult is a stepparent. Since it is likely that family physicians will have more stepfamilies in their patient populations than in previous times, it is important for physicians to be aware of the characteristics of stepfamilies that are not present in intact nuclear families. These characteristic are (1) the formation of the stepfamily out of loss, (2) a common history of some family members, (3) a parent-child bond that predates the couple bond, (4) a biological parent elsewhere, (5) children as members of two households, and (6) the legal limitations of the step relationship. Functions the physician might be able to serve for the stepfamily as its members work on the tasks associated with each characteristics are described. Recommendations for residency training and resources for physician and patient education are given.