The incidence and duration of breast feeding were determined via telephone questionnaires from a sample of 95 women who delivered healthy infants during the month of September 1982, in the greater metropolitan area of Portland, Oregon. This sample was limited in that the women were married, predominately white, over 25 years of age, and well-educated. According to the literature, these factors have a positive correlation with the incidence and duration of breast feeding. Consequently, the reported values for the incidence of breast feeding in the hospital of 88 percent and the duration of breast feeding for six months of 44 percent is higher than reported values on a national level. However, the average duration of breast feeding by women who had weaned their babies at the time of this survey (6.2 weeks) is consistent with other studies. The information obtained from the questionnaires was used to measure the association between the incidence of breast feeding and the amount of information women received during their pregnancy; the duration of breast feeding and support system(s); and the relationship between the incidence and duration of breast feeding to the social factors of income, education, age, and race. Chi Square was the statistic used to compare the distribution, of responses among the three subgroups: women who breast fed only, formula fed only, or both breast and formula fed. Significant associations were not observed between the incidence of breast feeding and information or between the duration of breast feeding and support system(s). There was, however, an observed significant association between the incidence of breast feeding and the social factor of income. Additional findings revealed that women most likely to breast feed had themselves been breast fed as a baby, had breast fed their other children, and did not smoke cigarettes. Possible explanations for these results are discussed. / Graduation date: 1983