The clinical relevance of foetal macrosomia (i.e. birth weight greater than or equal to 4000 gms) was investigated retrospectively using the 1987 figures of the "Bayerische Perinatalerhebung". 8591 (total n = 101931; 8.4%) newborns met the criterion for macrosomia and were compared with two groups of normosomic newborns (birth weight 2500-2999 gms and 3000-3999 gms). The problems, which may obscure correct prenatal diagnosis are discussed. The incidence of operative deliveries and birth injuries was increased. The duration of the deliveries was not prolonged in our study in contrast to published reports. The neonatal transfer-rate to a neonatal centre was higher in newborns, delivered by Caesarean section, compared with newborns delivered by the vaginal route. The perinatal and the maternal morbidity was higher, the perinatal mortality lower in the macrosomic newborn. According to our data, macrosomia represents and elevated perinatal risk.