The reliability and factor structure of the General Health Questionnaire-12 (GHQ-12) and the Rosenberg Self-Esteem scale (RSE) were evaluated in samples of Hungarian and Slovak early adolescents. The principal component analyses support the two-factor solution for GHQ-12 with subscales 'depression/anxiety' and 'social dysfunction'. Similarly, the RSE appears to be an instrument with a two-factor structure with subscales 'negative self-esteem' and 'positive self-esteem' in both samples. Reliability analyses of GHQ-12 and RSE total scales show satisfactory results, although the reliability figures of some components is lower. The factor structure of RSE component 'negative self-esteem' is less clear. Researchers need to be aware of the potential problems surrounding the negative item wording and make every effort to ensure that negatively-worded items are carefully constructed and easily interpreted by the population of early adolescents.