One hundred and fifty-six enuretic and 170 control children were examined to identify neurological abnormalities and group dissimilarities. Developmental and perinatal histories were checked and the Test of Motor Impairment administered. The enuretic group had greater fine and gross motor clumsiness and perceptual dysfunction than the control group. Children who had been small for gestational age, who had suffered asphyxia or shown neurological symptoms during the neonatal period had a higher risk of developing daytime or day- and night-time enuresis at a later stage. With the exception of toxaemia, perinatal risk signs were not seen in the children with night-time enuresis only, but they had the slowest growth rate. It is suggested that there are at least two different groups of enuretic children: those with daytime or day- and night-time enuresis, whose condition is associated with neurological damage; and those with an obvious delay in maturation of central nervous bladder control, who have night-time enuresis only.