This review critically appraises the role of chlamydospores as the main long-term survival propagules for Phytophthora cinnamomi. Evidence for the formation of chlamydospores in nature, as well as differentiation between thin- and thick-walled chlamydospores, is examined. Limited evidence was found for the occurrence of thick, as well as thin-walled chlamydospores. Information on the survival properties of the commonly occurring, thin-walled, chlamydospores is presented. Gaps are identified in our understanding of their behaviour in the natural environment, the length of time they survive dormant in soil and the factors that stimulate their germination. These are important issues that need to be addressed before we can adequately develop management strategies to control the spread and impact of P. cinnamomi.