Findings from a study of 47 children 4 to 12 years old who received tonsillectomies at a children's hospital indicated that adjustment before hospitalization was the strongest predictor of postsurgical adjustment. However, certain temperamental and mother-child relationship factors also were strongly related to and predictive of posthospitalization outcomes. Children who displayed the most positive reactions were temperamentally more rhythmical (i.e., had regular, predictable behavior), more approaching to new experiences and people, more adaptable to change and positive in mood, and more responsive. Although family adaptability and cohesion were not significantly associated with children's reactions to hospitalization, maternal trait anxiety and maternal overprotection, rejection, and overindulgence of the child were correlated with poorer adjustment. The findings have practical implications to helping children adjust more effectively to surgery and hospitalization, and they contribute to our understanding of resiliency and vulnerability in children.