OBJECTIVES: We report the development of an instrument to assess feelings about self-injection of growth hormone (GH) in adolescents with growth disorders. METHODS: Adolescents (age 11-19 years) in 2 cohorts (UK N=74 and USA N=98) completed a 10-item GH questionnaire, as well as health-related quality of life (HRQOL), functional status scales, self-control, and self-esteem scales to assess external validity. The GH and HRQOL questionnaires were repeated in 2-4 weeks. RESULTS: The GH questionnaire contains 10 items in 2 subscales (feelings, injection issues) and a total summary score, with higher scores indicating better acceptance of GH. Internal consistency reliabilities were a=0.77 Summary Score, a=0.68 Feelings, and a=0.78 Injection Issues, with overall test-retest reliability 0.72, and no floor or ceiling effects. Significant summary score correlations with external validity scales were 0.42 HRQOL, 0.34 functional status, 0.25 self-control. Mean summary scores did not differ significantly by cohort, age, gender, or diagnosis (range 4.0-4.4 points). The Injection Issues component was significantly associated with all VSP-AM subscales and total score (all p<0.01), whereas the Feelings component was significantly correlated with self-esteem, well-being, physical health and the total score (all p<0.01) as well as with teachers (p<0.05). CONCLUSIONS: The GH Injection Questionnaire is both a reliable and valid measure of attitudes for adolescents with growth disorders. It measures different constructs than other instruments. Adolescents who were more comfortable with GH injections had higher HRQOL, functional capacity, and self-control.