This investigation has established the possibility of survival of unfertilized mouse eggs with extracellular ice formation in glycerolated modified Locke''s solution at -10[degree]C for periods up to 3.5 hours. Survival of eggs so treated was evaluated by progeny development after transplantation into foster mothers. Microscopic observations during freezing and thawing indicated that eggs survive exposure to extracellular ice formation but not intra-cellular ice. It was suggested that cellular dehydration, by both glycerol and extracellular ice formation during slow cooling, favors survival in the supercooled condition.