Background and Purpose: This study aims to develop a task performance scale and a contextual performance scale for clinical nurses and to test the scales psychometrically. Methods: This study was carried out in two phases in a private hospital group. During the first phase, the initial scales were developed, and then the validity and reliability of the scales were analyzed; 154 nurses participated in the second phase. Results: The task performance scale consisted of two factors (total variance explained: 75.87%); the contextual performance scale consisted of three factors (total variance explained: 74.05%). The content validity indexes of both scales were 0.99. The Cronbach's alpha coefficients of both scales were 0.98. The test-retest reliability and inter-rater agreement of the scales were also good. Conclusions: The scales can contribute to nursing literature and hospital managers in assessing the performance of clinical nurses.