Background. It is our contention that both categorical and dimensional approaches to diagnosis are important for clinical work and research alike, and that each approach has its drawbacks and advantages. As the processes toward developing DSM-V and ICD-11 progress, we suggest that another exclusively categorical revision of psychiatric taxonomies will no longer be sufficient and that adding a dimensional component is a necessary step if these taxonomies are to continue serving the future clinical and research needs of psychiatry as they have so effectively done in the past. Method. We begin the paper with a review of terminology related to categories and dimensions and briefly review literature on advantages and disadvantages of both approaches. Results. A review of relevant literature supports both the need for and feasibility of augmenting traditional categorical diagnoses with dimensional information. Conclusion. We conclude with a proposal for preserving traditional categorical diagnostic definitions, but adding a dimensional component that would be reflective of and directly referable back to the categorical definitions. We also offer a specific proposal for adding a dimensional component to official taxonomies such as the DSM and the ICD in a way that fully preserves the traditional categorical approach.