Abstract: Geothermal brines are passed through a bed of an anionic resin selective to the removal of boron while maintaining a pH value between about 4 to 5.5 to load the boron on the resin from which the boron is thereafter recovered. If the brine contains large quantities of constituents have Lewis acidities greater than boric acid, these constituents are preferably removed before the boron is recovered. The invention is particularly applicable to geothermal brines of temperature above ambient, e.g., 90.degree. C. and above, such as 95.degree. C. and above.