The Sexual function-Vaginal changes Questionnaire (SVQ), was developed to investigate sexual and vaginal problems in gynaecological cancer patients. The instrument consists of 20 core items, measuring sexual interest, lubrication, orgasm, dyspareunia, vaginal dimensions, intimacy, sexual problems of partner, sexual activity, sexual satisfaction, and body image. Seven additional items assessing current levels of sexual and vaginal problems compared to pre-diagnosis are intended to be used only once in longitudinal studies. The SVQ was validated in two ways: first, the comprehensibility of each item was investigated through combined quantitative and qualitative assessment of patient-observer agreement in 75 gynaecological cancer patients, second, multitrait analyses and principal component analyses were applied to responses from 257 patients with cervical cancer to investigate the scale properties. The level of agreement between the patients' and the observer's ratings was high (median overall agreement 0.84, range 0.46–1.00; median kappa: 0.80, range 0.52–1.00). From the 10 items applicable to all patients, three scales were hypothesized: intimacy, sexual interest and global sexual satisfaction. For sexually active respondents an additional two scales were hypothesized: vaginal changes and sexual functioning. The psychometric analyses confirmed these scales. The internal consistency of the scales ranged 0.76–0.83 (Cronbach's alpha). The study supports the validity and reliability of the SVQ. Copyright © 2003 John Wiley & Sons, Ltd.