The objective of this study was to examine the factor structure of Achenbach's Child Behavior Checklist, using confirmatory factor analysis, in a group of pediatric oncology patients in Taiwan and to compare the competence and behavioral/emotional problems scores of these children with normative scores to assess competence and emotional/behavioral problems of Taiwanese children with cancer. Subjects included parents (124 mothers and 22 fathers) of 146 pediatric oncology patients who completed the measures. Factor loadings of the overall fit indices for the study subjects yielded or approached satisfactory results for all syndromes, except for aggressive behavior. The indices for both internalizing and externalizing syndromes also showed good model fit. Taiwanese children with cancer had significantly lower competence scores on the Child Behavior Checklist/4-18 than did Achenbach's sample, except Taiwanese girls with cancer, who had higher activity competence scores, but these scores were not statistically significant. Taiwanese boys with cancer had significantly higher scores on all of the emotional/behavioral problems, but had lower delinquent behavior, aggressive behavior, and externalizing syndrome scores. In contrast, girls with cancer had significantly higher scores on somatic complaints and internalizing syndrome, but significantly lower aggressive behavior and externalizing syndrome scores. Taiwanese adolescents with cancer had significantly lower competence scores compared with normative scores, with the exception being that the adolescents in the current study had significantly higher school competence scores. These adolescents also had significantly fewer attention problems but tended to have more somatic complaints. These findings clearly indicate that healthcare for children with cancer should include psychological services to prevent long-term emotional/behavioral problems.