Provided are an internal olefin sulfonate composition which shows excellent hue stability and excellent smell stability even when preserved for a long period of time, and a method for preserving an internal olefin sulfonate. The internal olefin sulfonate composition according to the present invention comprises an internal olefin sulfonate, one or more kinds of alkaline agents selected from among an alkali metal hydroxide and an alkaline earth metal hydroxide and water, wherein the content of the alkaline agents is 0.2 to 15 mmol inclusive per mol of the internal olefin sulfonate. The method according to the present invention for preserving an internal olefin sulfonate comprises mixing the internal olefin sulfonate at least with an alkaline agent to give a composition wherein the content of the alkaline agent is 0.2 to 15 mmol inclusive per mol of the internal olefin sulfonate.
