Background:The increasing ethnic diversity in the United States necessitates a study of variations in infant feeding patterns among ethnic groups. This study was conducted as part of Hawaii's surveillance system to identify infant feeding patterns in Hawaii; specifically, to identify factors influencing duration of breastfeeding among ethnically diverse mothers.Methods:All women who delivered an infant in Hawaii between January 1 and March 31, 1989, were mailed surveys 14 to 19 months after delivery. Fifty-one percent (n= 2011) of women responded, of whom 1574 (78%) did some breastfeeding and are included in the analysis of prediction of weaning (cessation of breastfeeding). Cox regression (survival) analysis was used to predict weaning.Results:The median duration of breastfeeding was 150 days; 45 percent of infants were still breastfeeding at age 6 months and 16 percent at age 1 year. Factors associated with early weaning were Japanese ethnicity; mother born in a country other than the United States, Japan, or the Philippines; first language other than English, or two languages at home; employed full-time outside the home; introduced formula or fruit before age 6 months; received formula from the WIC program; and stopped breastfeeding for convenience, breast problems, problems getting breastfeeding started, insufficient milk, baby refusing the breast, and a sick baby. Factors associated with late weaning were older maternal age; college education; living on a rural island; previous breastfeeding experience; helpful breastfeeding advice from family or friends; receiving WIC for breastfeeding mothers; introducing the cup before age 6 months; and not giving fruit to the baby.Conclusion:In Hawaii, programs that address how and when to introduce foods, use of formula, and management of outside employment and breastfeeding should be made available to those groups of women at risk for early weaning to lengthen their duration of breastfeeding.