Abstract
For 27 years annual figures have been kept of all infants weighing 2500 g or less born in the maternity department of the Northern General Hospital, Sheffield. The initial neonatal mortality rate (death within the first four weeks after birth) was then around 30% and is now 10%. This reduction is partly due to a decreased mortality rate among the individual weight groups but also to an increasing number of larger infants and a decreasing number of infants of low birth weight in the "high-risk" category.