Many preterm infants may experience so-called minor developmental disorders; however, in general, the problems in motor behavior are not detected until school age. To introduce therapies aimed at the prevention of these problems, we need to increase our knowledge of motor function and dysfunction at early age. The present study focused on the organization of reaching movements in full-term and preterm infants without cerebral palsy. The reaching behavior of premature infants (n ϭ 63) was assessed longitudinally at the corrected ages of 4 and 6 mo. Clinical assessments were made at 6 and 12 mo of age. On the basis of the infant's morbidity during the early stay in the neonatal intensive care unit, the preterm infants were allocated into a high-risk and a low-risk group. Results from a previous study in full-term infants (n ϭ 13) were included. Kinematics of reaching movements in supine position were measured, and the analysis focused on movement velocity and movement units. A compound parameter of kinematic variables was created, reflecting the quality of reaching movements. The present study showed that at the age of 4 mo, low-risk preterm infants showed more often optimal reaching behavior than full-term and preterm high-risk infants. This better reaching performance was related to a better general motor and behavioral development during the first year of life. At the age of 6 mo, the advantage of the low-risk group in reaching behavior had disappeared and a disadvantage in the form of nonoptimal reaching behavior of the high-risk group emerged. There is an increasing awareness that many preterm infants may experience subtle long-term morbidities. Usually these so-called minor developmental disorders, such as clumsiness and specific learning disorders, are identified first at school age (1-3). It has been questioned whether these minor developmental disorders can be detected at early age, so that intervention aiming at the prevention of problems that interfere with academic achievement could be introduced timely.Recently, evidence has been provided that early motor development in preterm infants without major developmental disorders differs from that of full-term (FT) infants. The majority of studies focused on postural development. They indicated that so-called "low-risk" preterm infants show significantly more often an exaggerated trunk extension (4, 5) or "transient dystonia" (6, 7) than FT infants. Van der Fits et al. (8), who studied the development of postural adjustments during reaching, reported that low-risk (LR) preterm infants showed an excessive amount of postural activity. Moreover, the postural adjustments of the preterm infants were temporally disorganized and could not be modulated to task-specific conditions, such as the velocity of the reaching arm and sitting position. The mild dysfunctions in postural control of preterm infants are related to a poorer quality of reaching and grasping at the age of 1 y (9, 10) and possibly also to motor dysfunctions (7) or learning problems (6) at school age...