This thesis aims to study the nature of, and find appropriate production parameters for four Icelandic low-temperature geothermal fields, Laugarnes in Reykjavík, Áshildarholtsvatn in Skagafjörður, Skútudalur near Siglufjörður and Laugaland in Eyjafjörður. With this objective, first the long- term production history of each field was simulated by lumped parameter models to estimate essential properties of the systems and to calculate future pressure change predictions. After that, possible future cooling was also estimated by using analytical thermal models. Finally, sustainable production scenarios were developed for each field, based on these models.