Introduction:Quality of life in patients with acute pharyngitis or tonsillitis is significantly lower than in healthy persons, and it should be taken into account when efficacy of new therapeutic options is investigated.Objective:The aim of this study was to develop and validate a reliable instrument that can measure quality of life in adult outpatients with sore throat caused by acute pharyngitis or acute tonsillitis.Method:The study was of a cross-sectional type, and assessed reliability and validity of newly developed questionnaire for measurement of quality of life in adult outpatients with sore throat (STQoL) caused by acute pharyngitis or acute tonsillitis. It was conducted on a sample of 282 patients, with mean age 39.0 ± 14.8 years, male/female ratio 104/178 (36.9%/63.1%).Results:Final version of the STQoL scale with 21 items showed excellent reliability, with Cronbach’s alpha 0.949. It was temporally stable, and both divergent and convergent validity tests had good results. Factorial analysis revealed three domains, Social/psychic aspects, Physical aspects and Environmental aspects of sore throat related quality of life.Conclusions:The STQoL scale is reliable and valid specific instrument for measuring sore throat related quality of life, which is an important treatment outcome in patients with acute pharyngitis or tonsillitis.