Background The planning, implementation, finalisation and reporting of high-quality research depends on the knowledge, skills and competencies of the many individuals who make carrying out the research possible. Aims This study aims to develop a valid and reliable scale in order to identify the scientific research competencies of nursing professionals at undergraduate and graduate level. Methods This methodological study was carried out on 937 nursing personnel, 422 (45%) of whom were academic members and 515 (55%) were undergraduate students. The Anxiety Scale Towards Research and the Attitude Scale Towards Scientific Research were used for the criterion validity. Results The Scientific Research Competency Scale comprises 57 items in four sub-dimensions named as ‘technical skills’, ‘attitude and behaviours’, ‘estimation capacity’ and ‘foreign language skill’. The Cronbach alpha, Guttmann split-half and Spearman Brown reliability coefficients for the scientific research competency scale were, respectively, 0.98, 0.96 and 0.96. The sensitivity and specificity value, by which the research competency of individuals could be determined with minimum error, was indicated to be at 190 breakpoints of the scientific research competency scale. Conclusions As a result, the scientific research competency scale developed is a valid and reliable tool that can be used to determine the scientific research competencies of nursing professionals.