 The 'Schedule for the Evaluation of Individual Quality of Life – Direct Weighting' (SEIQoL-DW) is an instrument developed to measure individual quality of life. Although this instrument has been used in numerous studies, data on validity and reliability are sparse. This study aimed to examine aspects of validity, reliability and responsiveness of the SEIQoL-DW on data obtained in adults with congenital heart disease, by using the new standards of psychological testing.