This data was collected to write an extensive review on organic compounds in geothermal fluids as part of the REFLECT (Redefining geothermal fluid properties at extreme conditions to optimize future geothermal energy extraction). The data is mainly focussed on geothermal sites were organic compound data was reported in the literature. It includes data from the literature (Feldbusch, 2016; Vetter, 2012; Brehme et al., 2019; Westphal et al., 2019; Sanjuan et al., 2016) as well as own data that was analysed at the GFZ German Research Centre for Geosciences in section 3.2 (Organic Geochemistry). It comprises 130 samples from 19 different sites including DOC, organic acid anion as well as main inorganic anion concentrations, well depths, and reservoir temperatures of various geothermal sites in Europe. Due to confidentiality agreements Site names are all given in ID’s which are fully explained in the publication “Organic compounds in geothermal fluids – a review” when available. Sample ID’s are also given if the samples, both from the literature or own samples were measured at GFZ German Research Centre for Geosciences. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement nº 850626 (REFLECT).