In spite of numerous recent outcome studies of extremely low birth weight (ELBW) infants, no data exist on their development prior to term. In this study we traced and compared the neurobehavioral development of 251 ELBW (less than 1,000 g) and 240 low birth weight (LBW; 1,000 g-2,500 g) preterms born between 1995 and 2004 from 32 to 37 weeks postconceptional age (PCA), using the Neurobehavioral Assessment of the Preterm Infant (NAPI; Korner & Thom, 1990). Compared to the original NAPI cohort of 521 infants (born 1983-1989), the ELBW and LBW infants were at higher medical risk, displayed weaker motor development, a tighter scarf sign and popliteal angle at all or most PCAs, and a weaker cry at older PCAs; they did not differ in irritability and percent asleep ratings. Few differences were noted between the ELBW and LBW groups. Research is now needed to determine whether the 1995 to 2004 NAPI values of ELBW and LBW infants at 32 to 37 weeks PCA are predictive of later outcome of high-risk preterms. (Contains 3 tables and 7 figures.)