Recent work on anhydrobiosis in invertebrates is reviewed. I introduce definition and classification of cryptobiosis, and review the distinctive features and extremely high stress tolerance of anhydrobiotic invertebrates. Most anhydrobiotic invertebrates have evolved various kinds of behavioral, morphological, physiological and physical adaptations to reduce water loss during induction of anhydrobiosis. Trehalose is known as a common compatible solute in anhydrobiotic organisms from unicellular organisms to invertebrates and higher plants. Trehalose may provide effective protection against desiccation because it has superior biochemical and physicochemical properties for stabilizing membranes and biomolecules including proteins and lipids. Recent work also indicates several possible kinds of molecules involved in induction of anhydrobiosis. The adaptations necessary for successful induction of and recovery from anhydrobiosis vary greatly among taxa of invertebrates. Understanding the diversity of anhydrobiosis in invertebrates would be a key to elucidate evolutionary scenarios in anhydrobiosis.