Although the tissue solvent and bactericidal properties of sodium hypochlorite are well known, the effective shelf-life of prepared sodium hypochlorite solutions is not known. The stability of sodium hypochlorite is adversely affected by exposure to high temperature, light, air, and the presence of organic and inorganic contaminants. The purpose of this study was to investigate the variables of storage conditions and time on the tissue-dissolving capacity of three different concentrations of sodium hypochlorite. Fresh frozen human umbilical cord was used as the tissue sample for this experiment. Tissue samples were dissolved at time intervals ranging from 1 day to 10 wk in 5.25%, 2.62%, and 1.0% solutions of sodium hypochlorite. The tissue-dissolving ability of 5.25% sodium hypochlorite remains stable for at least 10 wk. The tissue-dissolving ability of 2.62% and 1.0% sodium hypochlorite remains relatively stable for 1 wk after mixing, then exhibits a significant decrease in tissue-dissolving ability at 2 wk and beyond.