Ultrasound assisted ring-opening of epoxides with 1,2-diphenyldiselenide in PEG-400/H2O in the presence of sodium dithionite has been developed, affording β-hydroxy selenides with high regioselectivity in good to excellent yields. Importantly, the present protocol is very practical and highly efficient since it does not require the use of expensive and unpleasant smelly reagent.