OBJECTIVES: To help clinicians determine the presence of suicidality, the C-SSRS was developed in US English and contains suggested probes to assess suicidal ideation and behaviour, their severity, and lethality of suicidal attempts.  Prior to use in an international study to investigate suicidality, the clinician rated C-SSRS had to be translated into 45 languages for 33 countries.  A rigorous methodology was required to ensure conceptual equivalence and cultural relevance across languages. METHODS: The process was conducted by specialists in each target country, following a standardized methodology: 1) two forward translations by native target language speakers; 2) comparison and reconciliation of the translations; 3) back translation by a native English speaker; 4) comparison of original and back translation; and 5) review by a clinician. RESULTS: Cultural and linguistic challenges emerged during the process. On the cultural level, the differences in the approach to suicide and its methods based on differences in tradition and availability of means required finding suitable alternatives in the target languages. On the linguistic level, it was important to differentiate between medical and psychiatric hospitalisation after a suicide attempt and appropriate solutions across languages had to be found. The process revealed an area of ambiguity in the original rating instructions which had to be clarified in the translations. Examples of these and other challenges and  their solutions will be discussed in the presentation. CONCLUSIONS: The 45 language versions, of the C-SSRS (a total of over 90 translations now exist), were established according to a rigorous methodology to ensure conceptual equivalence and cultural relevance across languages. The translations may now be used in international studies to assess suicidal ideation and behaviour and facilitate the comparison and pooling of data. The analysis of the psychometric results will be necessary to see if and how suicidal ideation and behaviour compare across countries and cultures.