Background: Remarkable advances in educational measurement have proved need to the implementation of modern and appropriate methods of clinical evaluation. This study was carried out to compare the effect of applying direct observation procedural skills and routine evaluation method on clinical skills of nursing students., Methods: This randomized clinical trial was conducted on students of Nursing Army College, Tehran, Iran. After obtaining approval from the Ethics Committee of the Baqiyatallah University of Medical Sciences Research Deputy, all nursing students and instructors who agreed to participate in this study sign the informed consent. The participants were randomly assigned into intervention and control groups. After the teachers were trained and an inter-raters reliability test was conducted, evaluation was performed through DOPS in the intervention group while the control groups were evaluated through the routine method. Assessment checklists for two procedures (Intra venous catheterization and change dressing) were valid and reliable. Finally data were analyzed through descriptive and analytical statistics (Chi-square, t-test, Repeated Measure ANOVA) using SPSS version 16., Results: No significant difference was observed between the two groups in terms of demographic variables (P>0.05), but a significant difference was observed between intervention and control scores (P=0.000). In other words, application of DOPS has improved clinical skills of the students significantly., Conclusion: Using this new method improved the students' scores in clinical procedures implementation; therefore, we suggest that nursing colleges apply this evaluation method for clinical education.