A method for generating decay-classification systems was developed for coarse woody debris (CWD). This method was used to generate a decay-classification system for wet eucalypt forest CWD, and trialled on over 120 pieces of CWD sampled from post-logging coupes in southern Tasmania. The developed system was easier to implement than systems currently used in Tasmania, with logs being explicitly classified into specific classes without the possibility of character states being split between adjoining classes. The classes were well-balanced and correlated with age and residual density of the wood. Density variance within the classes was at least as good as the currentlyused systems (e.g. mean Coefficient of Variation within classes was 21.3% for new and current systems). The method used to develop the system is transferable to other forest types, and has the flexibility to construct decay-classification systems to suit any predetermined number of classes. The system lends itself to the construction of a dichotomous classification key, which creates an explicit categorisation process that is easy to follow and, in time, allows users to memorise the criterion for each class in turn. The developed classification key allows a simple progression when used in the field whereby once a CWD piece has been classified, the user need not continue further through the key.