In order to document in detail the developmental course of qualitative aspects of early spontaneous motility in intrauterine growth-retarded infants, sequential videotape recordings were made in 19 preterm infants with a birth weight below the 5th percentile. The quality of general movements (GMs) was studied longitudinally during the preterm and postterm period until approximately 20 weeks corrected age, using Prechtl's method of quality assessment. An abnormal quality of GMs was present in 15 out of 19 infants. Compared to a low-risk group, consisting of appropriate-for-gestational age preterm infants, the proportion of infants with normal findings on brain scans who had an abnormal quality of GMs was high. The presence of 'abrupt chaotic' GMs was related to late fetal heart-rate decelerations and ischaemic alterations of the placenta. The quality of GMs normalized before or during the third month postterm in most infants with abnormal GMs. In four infants, the GMs did not normalize during the study period. The quality of fidgety movements was, in particular, a marker for neurological outcome at 24 months. This study demonstrates that intrauterine growth retardation may cause prolonged, but in most cases transient brain dysfunction; the qualitative assessment of GMs may help to identify infants at increased risk for neurodevelopmental abnormalities.