Background: In Indonesia so far there has been no standardized instrument for disaster competence, so it is considered important by researchers to develop an instrument for assessing competence in disaster nursing, especially earthquakes and volcanoes, considering that most of Indonesia's regions are prone to disasters. Objective: To develop a non-test (observation) instrument for disaster nursing assessment referring to the ICN competency framework and validate its content based on the expert agreement with the calculation of the Aiken index coefficient. Method: using Design-Based Research by referring to Anderson and Shattuck's model, where through this design the observation instrument is developed in the form of a rubric and its assessment by the rater during the disaster simulation. Results: The results obtained were all items in the valid or very valid category because the V (Aiken) index values ranged from 0-1, while the lowest was 0.75 and the highest was 0.95. For the equipment, the Aiken index for the rubric instrument for the assessment of disaster nursing competence was 0.85 with the high category. Conclusion: The researcher has proven the validity of the instrument content with expert agreement using the Aiken agreement index, or the instrument developed has been proven valid.