During three months in 1975 admissions to 17 of the 21 special-care baby units in the North-west Thames region were analysed by birth weight and category of care. Of the 1718 babies admitted, one-third needed only observation. Neonatal intensive care formed only a small proportion of the work load in most units. Considerable variation in the pattern of admissions was found. There was some evidence of concentration, about 100 babies being transferred for urgent medical or surgical reasons, and the work load of one unit suggested that it was servine as a referral centre. It is concluded that the quality of care given to some infants needing intensive care might be improved by greater concentration, and that some units should review their admission policies in order to prevent unnecessary postpartum separation of mother and baby. © 1979, British Medical Journal Publishing Group. All rights reserved.