OBJECTIVES: The Neuropsychiatric Inventory (NPI) was developed in US English to assess, through interviews with caregivers, ten behavioral disturbances occurring in dementia patients: A. Delusions, B. Hallucinations, C. Agitation/Aggression, D. Depression/Dysphoria, E. Anxiety, F. Elation/Euphoria, G. Apathy/Indifference, H. Disinhibition, I. Irritability/Lability, and J. Aberrant Motor Behavior. Two neurovegetative areas were added afterwards: K. Sleep, and L. Appetite and Eating Disorders. Screening questions assess the presence or absence of changes in behaviors in the patient. If the behavioral change is present, then, subquestions (n=7 to 9) are asked to evaluate behaviors in terms of frequency, severity, and distress. The objective of this study was to present the challenges faced during the translation of the NPI-12 into 74 different languages representing ten language families. METHODS:  The NPI was translated in most languages with a process including: 1) Concept definition with the developer 2) Forward/backward translation step; 3) Final reconciliation; 5) Clinician review; and 6) Proof-readings. RESULTS:  The translation process did not reveal any cultural issues since most of the concepts assessed were cross-culturally relevant. The psychiatric terms (e.g., delusions, euphoria, etc.) were carefully translated with the clinician input in each country. When a literal translation was impossible, synonyms or periphrases were used. Most of the challenges identified were linked to the use of idiomatic/colloquial content, such as the use of “talk big” in subquestion 6 (Does the patient “talk big”) in section F, or the use of “flying off the handle” in subquestion 1 (Does the patient have a bad temper, flying “off the handle”…) in section I. In some languages, idiomatic expressions were available to express the same notions. However, in many languages either a synonym or a circumlocution was needed. Examples are presented. CONCLUSIONS:  A rigorous methodology was essential in producing NPI translations conceptually equivalent to the US English original.