Conscientious objection poses ethical dilemmas frequently encountered by nurses, allowing them to prioritize personal beliefs in caregiving. However, it may also be viewed as a stance jeopardizing patients’ healthcare access. There is no measurement tool to measure conscientious objection in nurses. This study aimed to develop a measurement tool for nurses’ conscientious objection attitudes. This research is a methodological study conducted with a total of 261 nurses in Turkiye. Following content validity assessments by ten experts, a 29-item draft scale was (...) developed. Exploratory and confirmatory factor analyses examined the factor structure, and reliability was assessed via the Spearman-Brown coefficient, intraclass correlation coefficient (ICC), and Bland Altman plot. Cronbach’s alpha estimated internal consistency and discrimination, which were evaluated by comparing lower and upper 27% groups. The Nurses’ Conscientious Objection Attitude Scale (COAS-N) comprises 29 items and three sub-dimensions (prioritizing professional values, prioritizing personal values, and requesting the right to conscientious objection). Cronbach’s alpha for the entire scale is 0.81. Validity and reliability were established for the newly developed scale measuring nurses’ conscientious objection attitudes. (shrink)