THE CHAPTER ON CELLULAR CONCRETE WAS FIRST presented in ASTM STP 169B in 1978 and was authored by Professor Leo M. Legatski [1]. In ASTM STP 169C in 1994, the chapter was authored by his son Leo A. Legatski [2] who updated various sections and stressed new applications of the material. The author acknowledges both father and son for their earlier contributions as their work provides the background for this edition. In the interest of consistency, some of the fundamental aspects of the earlier publications are retained in this chapter. The current edition updates the topics, introduces new information on the material properties and applications of cellular concrete, and includes up-to-date references.