Minority stress is a relatively new concept that has emerged from the concept of stress. Its popularity among researchers who are interested in minority groups is increasing. Minority stress refers to the experiences of stigma, rejection and violence by the majority of society as experienced by the minority. The concept can be operationalised in a number of ways, for instance via a questionnaire such as the Sexual Minority Stress Scale (SMSS) presented in this paper. It concerns a clearly defined concept of minority stress and uses some stress indicators. It was translated and adapted into Polish. This paper presents the results of statistical analysis based on answers of 206 individuals describing themselves as homosexual and 62 describing themselves as bisexual. High psychometric results of the questionnaire indicate that SMSS can be used in research on minority stress in bisexual and homosexual individuals. However, further research is required to verify its usefulness in the clinical setting as a screening tool to diagnose those who may be at risk from high levels of minority stress.