Health-related quality of life (HRQoL), conceptualized as patients' own evaluations of their health status, is an important criterion in evaluation health and health care and in the treatment of individual patients. Until now, few systematic attempts have been made to develop instruments to assess the HRQoL of children using such a conceptualization. This article describes the conceptualization and results of a study aiming to develop such an instrument for children aged 6-15 years using their parents as a proxy. The feasibility and psychometric performance of the instrument were evaluated in a study of 77 patients of the paediatric out-patient clinic of Leiden University Hospital. For each of the a priori-defined domains, a parent form scale could be constructed with satisfactory reliability and moderate correlations with the other scales. Only some of the parents indicating health status problems also signalled negative reactions to these problems. This is, in our view, a strong argument for the distinction between health status and quality of life (QoL). The correlation coefficients between the parent form and a children's questionnaire were low. Overall, the psychometric performance of the TACQOL parent form looks promising, which suggests that this instrument--with some modifications--can indeed be used to assess group differences in HRQoL in children. The results, however, should be replicated in larger samples, currently under study. The relation between parents' proxy reports on the HRQoL of their children and children's self-reports needs further investigation.