Compared with conventional Rankine cycles that use water as the working fluid, organic Rankine cycles (ORCs) can produce shaft work/power from low-to-medium temperature heat sources more efficiently. Other advantages of ORCs include long service life, low maintenance cost and improved part-load characteristics. ORCs have been applied to power generation from different heat sources such as industrial waste heat, solar thermal, biomass and geothermal. This work focuses on the application of ORCs for geothermal power generation, considering different possible ORC configurations. A generic design method involving thermodynamic analysis and process modelling is developed, with the aim of assessing the system performance as well as determining the optimal system configuration and operating conditions. A literature case study is presented to illustrate the proposed approach.