Newborn mortality accounts for about one-third of deaths in children under five. Neglecting this problem may undermine the fourth Millennium Development Goal of reducing child mortality by two-thirds by 2015. This study was conducted in Tanzania, where an estimated 32/1000 infants die within the first 28 days. Our objective was to describe newborn care practices and their potential impact on newborn health. We interviewed two purposive samples of mothers from Pemba Island, a predominantly Muslim community of Arab-African ethnicity, and one of Tanzania's poorest. The first sample of mothers (n = 12) provided descriptive data; the second (n = 26) reported actual practice. We identified cultural beliefs and practices that promote early initiation of breastfeeding and bonding, including 'post-partum seclusion'. We also identified practices which are potentially harmful for newborn health, such as bathing newborns immediately after delivery, a practice motivated by concerns about 'ritual pollution', which may lead to newborn hypothermia and premature breast milk supplementation (e.g. with water and other fluids) which may expose newborns to pathogens. Some traditional practices to treat illness, such as exposing sick newborns to medicinal smoke from burning herbs, are also of concern. It is unclear whether the practice of massaging newborns with coconut oil is harmful or beneficial. Interventions to reduce neonatal mortality need to identify and address the cultural rationales that underlie negative practices, as well as reinforce and protect the beliefs that support positive practices. The results suggest the need to improve use of health services through improving health worker communication skills and social management of patients, as well as by lowering healthcare costs.