This is a study of infant feeding practices among Bedouin tribes residing in the Negev, Israel. The objectives are: the evaluation of changes in infant feeding practices during the first year of life and their relationship to physical growth of children and on gastrointestinal and respiratory diseases during the first year of life. The information obtained covers 5,000 mother-infant pairs. Two samples have been identified; one was identified at birth and a subsample of these births was followed for a period of 5-8 months. Another sample of children was identified at 6 months of age and followed prospectively to 18 months of age. Several manuscripts based upon the analyses of these data have been published which include: undernutrition among Bedouin Arab infants and effect of infant feeding practices on infant growth, the 40-day rest period and infant feeding practices, and seasonality of births among Bedouin Arabs. The manuscript on perinatal determinants of infant feeding practices has been accepted for publication by the Journal of Pediatric and Perinatal Epidemiology. The manuscript on infant feeding practices as related to morbidity is still in preparation.