Several interesting surveys on the use of diagnostic systems have been conducted over the past two decades, initially focused on ICD-9 and DSM-III and then on more recent editions of these systems. They have reported on the extent and perceived value of their use as well as offered recommendations for future systems. The widest survey to date is that on ICD-10 and related systems recently conducted by the WHO Committee on Evaluating and Updating the ICD-10 Mental Health Component and the WPA Section on Classification and Diagnostic Assessment. It involved the participation of 205 psychiatrists from 66 different countries across all continents. Comparing the two most visible diagnostic systems, it found that ICD-10 was more frequently used and more valued for clinical diagnosis and training and that DSM-IV was more valued for research. Accessibility to diagnostic manuals and training appeared limited, particularly concerning the research criteria, primary care, and multiaxial versions of ICD-10. It also elicited structural and strategic recommendations for the elaboration of new diagnostic systems. It is suggested that it may be useful to widen the scope of future surveys, to additionally include policy makers, patients and families, and to conduct naturalistic studies of clinical care.