Despite the launching of a national breastfeeding promotion campaign in Bangladesh in 1989, exclusive breastfeeding rates remain low. To understand mothers' perceptions of the campaign messages and the reasons for current practices, a random sample of 1100 lower middle class mothers in Dhaka, with infants aged 0-6 months, were interviewed in 1995. Although 99 per cent of mothers fed colostrum within 3 days of delivery, 92 per cent also gave one or more traditional prelacteals, and 68 per cent gave postlacteals. This could be due to ambiguity of the message, which simply advocated giving colostrum without indicating its exclusive use, thereby appearing compatible with traditional perceptions that colostrum alone is insufficient. Ninety-nine per cent of mothers reported hearing the breastfeeding messages or receiving advice, and 97 per cent stated that they understood the meaning of exclusive breastfeeding. But this concept was not correctly understood, as many thought it meant feeding breastmilk and water. The prevalence of exclusive breastfeeding was 15 per cent, and complementary foods were introduced early (median 30 days). Many mothers doubted the message that breastmilk alone is sufficient for 5 months. Messages to promote improved breastfeeding practices in Bangladesh need to be revised to clear misconceptions.