BACKGROUND: There are currently no questionnaires to measure the knowledge of nurses about dementia or Alzheimer's disease care in the Spanish language.

OBJECTIVE: To validate the Spanish version of the Dementia Knowledge Assessment Tool 2 (DKAT2-Sp).

METHODS: The DKAT2 was translated into Spanish and then back-translated. The new Spanish version was validated in a sample of 361 members of the nursing staff from 24 nursing homes and a sample of 297 nursing students in Spain. Psychometric properties were assessed through an item analysis, a Rasch analysis, differential item functioning analysis, construct validity (known groups), and internal consistency (Cronbach's alpha).

RESULTS: The 21 items of the DKAT2-Sp fit the model well, showing a wide range of difficulty. Four items have differential items functioning between nursing professionals and students. The DKAT2-Sp shows acceptable internal consistency (Cronbach's alpha = 0.76 for nursing professionals and 0.83 for students). Scores obtained in the known groups test were as hypothesized (Nursing home staff mean = 15.57 versus Nursing student mean = 12.85; p 

CONCLUSION: The DKAT2-Sp is a reliable and valid questionnaire to measure knowledge about dementia in both nursing professionals and nursing students in Spanish-speaking contexts.