Freeze-induced injury is a commonly observed phenomenon with cultured fibroblasts from patients with I-cell disease (ICD). Cells from these patients have therefore not been widely available to investigators, which has inhibited the study of this complex disorder. Skin biopsies from three ICD patients, as well as fibroblast cultures derived from these biopsies, have been subjected to a series of freezing experiments. The results show that when standard freezing protocols are employed, skin biopsies from these patients, in contrast to cultured fibroblasts, tolerate freezing well. In addition, when subjected to prolonged incubation in the confluent state, fibroblast cultures will consistently withstand frozen storage and, upon thawing, will yield actively growing cultures, biochemically and morphologically indistinguishable from the cultures that were frozen. There was a direct correlation between incubation time at confluence and subsequent cell survival after freezing.