Abstract Background & Aim: The Achievement Motivation is the cause of successful behavior and efforts in students. This study aims to determine the relationship between achievement motivation and self-efficacy of clinical performance in nursing students. Material & Methods: This descriptive-Correlational study was conducted on 115 internship nursing students of Shahid Beheshti University of Medical Sciences. The sample was recruited by census. Data was collected by Hermans’ Achievement Motivation Questionnaire and self-efficacy in clinical performance scale and analyzed by descriptive, non-parametric tests and Spearman correlation coefficient using SPSS-PC (v. 16). Results: There was a significant relationship between achievement motivation and self-efficacy in clinical performance (r=0.61, P