Recovery of deuterium oxide (D2O) e.g., heavy water from lithium pentabo-rate, Li2B10O16.10H2O (represented as LiPB), solution in heavy water is achieved by using a mixed bed (MB) ion exchanger. Boron removal capacity for the strong base anion exchange resin was found to increase with an increasing concentration of boron in the inlet solution of ion exchange column. With 0.2 M LiPB (i.e., 2M Boron) the anion resin in the mixed bed showed four to five times the boron removal capacity observed with 0.001 M LiPB. This increased capacity is attributed to the existence of polymeric borate species at higher boron concentration. A similar high capacity for the strong base anion exchanger could be obtained in batch equili-bration of the resin with 0.2 M LiPB. However, column experiments with simple anion exchanger yielded boron slip from the beginning of the run but, nevertheless,nearly realized the LiPB concentration–dependent higher boron removal capacities mentioned previously. The mixed ion exchange method of D2O recovery appears to be a better alternative to the distillation method.