While suicidal behavior is not necessarily always related to the presence of a mental illness, most psychiatric conditions carry a higher suicide risk over the general population, and the lethality of suicidal behavior is clearly correlated with the presence of mental disorder. Hence, it is quite striking that suicide and related behaviour are barely addressed in the currently official classifications of mental disorders. The forecoming classifications DSM-V and ICD-11, to be due around 2012, should address the mentioned shortcomings of their predecessors. The best way to emphasize the importance of suicidal behavior is to facilitate its assessment across all mental conditions, and this should likely be done by means of dimensional assessment. Hence, both DSM-V and ICD-11 should include a dimensional module which would be complementary to the categorical module, and which would include, among other features, the assessment of suicide risk. As suicide is a behaviour linked to other relevant features also poorly covered in current nosology, such as impulsivity, guilt, and sometimes violence and psychosis, the dimensional assessment should also address all those psychopatological items. The categorical module should be refined and more data-driven. Other modules should include all the relevant information coming from biomarkers, physical health, psychological traits, social environment, treatment response, and family history, including family history of suicide. A major change in the classificatory systems should hopefully lead to better assessment of suicide risk and increased awareness on this issue by mental health care providers, resulting in more effective prevention of suicide.