Most theoretical fundamentals of geothermal geochemistry were established by the mid-1980s, as were numerous practical applications of these fundamentals to geothermal resource evaluation and management. Since that time, these geochemical tools have been refined to various degrees. Advances are discussed in the categories of sampling and analysis, exploration and resource evaluation, and resource management. Noted developments include: widespread use of high-performance liquid chromatography (HPLC); advances in spectral analysis; new and refined chemical geothermometers (especially using non-condensible gas species); analysis tools that enable fluid inclusion stratigraphy; ground surface CO2 flux measurement; integration of geochemical reaction models into numerical reservoir simulation; scaling and wellflow chemistry modification; new reservoir tracers and flow-line tracer enthalpy technology. Emphasis is placed on commercially applied technology, but academic developments are included.