The purpose of this study was to describe the characteristics of family physicians in Michigan who practice obstetrics and to identify important factors relating to a decision to discontinue obstetric practice. Questionnaires were mailed to all members of the Michigan Academy of Family Physicians (MAFP) who were listed as currently practicing obstetrics. Two hundred ninety-one questionnaires from the 357 mailed questionnaires were returned for a response rate of 81.5 percent. Two hundred thirty-five of the 291 respondents (80.8 percent) were practicing obstetrics in 1986. Twenty-two of the 235 physicians (9.4 percent) planned on discontinuing obstetric practice by early 1987. Reasons for discontinuing obstetrics included malpractice liability risk and cost and interference with lifestyle. Physicians who had recently discontinued or were planning to discontinue obstetric practice were significantly less likely than physicians practicing obstetrics to have a residency program affiliation (33 percent vs 58 percent). While malpractice concerns were found to be an important factor in deciding to discontinue the practice of obstetrics, practice arrangements and educational affiliations were other important factors that may be more amenable to change through educational or administrative interventions.