OBJECTIVE: This study aims to assess the development and the validity analysis of the Assessment of Risk Management in Health Care Questionnaire (AGRASS). METHODS: This is a validation study of a measurement instrument following the stages: 1) Development of conceptual model and items; 2) Formal multidisciplinary assessment; 3) Nominal group for validity analysis with national specialists; 4) Development of software and national pilot study in 62 Brazilian hospitals 5) Delphi for validity analysis with the users of the questionnaire. In stages 3 and 5, the items were judged based on face validity, content validity, and utility and viability, by a 1-7 Likert scale (cut-off point: median < 6). Accuracy and reliability of the questionnaire were analyzed with the Confirmatory Factor Analysis and the Cronbach’s alpha. RESULTS: The initial version of the instrument (98 items) was adapted during stages 1 to 3 for the final version with 40 items, which were considered relevant, of adequate content, useful, and viable. The instrument has 2 dimensions and 9 subdimensions, and the items have closed-ended questions (yes or no). The software for the automatic collection and analysis generates indicators, tables, and automatic graphs for the assessed institution and aggregated data. The adjustment indices confirmed a bi-dimensional model composed of structure and process (X2/gl = 1.070, RMSEA ≤ 0.05 = 0.847, TLI = 0.972), with high reliability for the AGRASS Questionnaire (α = 0.94) and process dimension (α = 0.93), and adequate for the structural dimension (α = 0.70). CONCLUSIONS: The AGRASS Questionnaire is a potentially useful instrument for the surveillance and monitoring of the risk management and patient safety in health services.