The purposes of this study were (1) to evaluate the usefulness of the Neonatal Behavioral Assessment Scale (NBAS) as a tool to assess the risk of later behavioral problems, (2) to analyze the relationship between neonatal behavioral characteristics and behavioral problems in childhood. Subjects were 77 very-low-birth-weight infants admitted to the NICU at the Nagasaki University Hospital, Nagasaki, Japan. The results suggest that behavioral characteristics such as poor motor performance, poor state regulation, and poor interaction ability in the neonatal period are risk factors for behavioral problems in childhood. The NBAS could help clinicians to identify neonates at risk of later behavioral problems.