We have studied the causes and outcome of obstetric brachial plexus palsy in all children born in Malmö during the 10-year period 1973-1982. Forty-eight of 25,736 live-born children (0.19%) were neonatally diagnosed as having a brachial plexus paresis. Twenty-five percent of these, i.e., one child in 2,000 liveborn, had a persistent palsy. The obstetric history was characterized by high birthweight, vertex presentation with shoulder dystocia and multiparity; and in two cases the mother had two children with brachial palsy. The children who recovered totally did so during the first few months. The prognosis for the more common upper brachial plexus, or Erb's, was more favorable than that for entire brachial plexus palsy. All the children with persistent palsy were afflicted with considerable reduction in arm function, resulting in varying degrees of handicap, such as not being able to use the palsied arm at all or not being able to perform certain tasks--writing properly, playing a musical instrument, doing the hair, wearing clothing with shoulder straps, etc. We wish to point out that, in several cases, obstetric brachial plexus palsy results in a lifelong handicap and that prevention and therapy are essential both in obstetric and in pediatric management.