In an attempt to assess the effects of early sibling visitation in a neonatal intensive care unit, 31 siblings (ages 3-12) of the hospitalized infant were randomly assigned to either a visit group (during first week of neonatal life) or a comparison group who visited only after the study was completed 3 weeks after birth of the neonate. Parents of both groups of siblings completed the Missouri Behavioral Checklist (MBCL) and Family Environment Scale (FES) in the first few days after birth and, again, 3 weeks after birth. All siblings were interviewed 3 weeks after birth of the neonate. Neither group experienced any increase in negative behaviors following the new sibling's birth. In fact, both groups showed some decrease in negative behaviors. In addition, the visitor group showed a significant decrease in negative behaviors on a specific subset of MBCL items. In addition, the visitor group was significantly more well informed about their sibling than the comparison group. J DevBehav Pediatr 11:7-12, 1990.