Stable isotopes give a powerful tool used in many applications (biogeochemistry, atmospheric science, greenhouse gases, paleoclimate, hydrogeology, geology, forensics etc) and, as such, isotope data should fit-for-purpose. To produce reliable data and make trustworthy interpretations, data produced in different laboratories should be comparable (be on the same scale) and compatible (be within target uncertainty). However, the uncertainty provided often involves only the measurement repeatability on a few runs. There are no commonly agreed ways of uncertainty estimations and some uncertainty components may be missing from considerations. Thereafter, use of basic quality control tools such as performance charts, quality control materials and lab-to-lab comparisons is of high importance. This multi-disciplinary session aims to address aspects related to the quality of stable isotope data starting from calibrations, uncertainty estimation as well as various tools used for quality control.