The teacher-centered learning methods provide fewer opportunities compared to student-centered methods. This study aims to determine the impact of the portfolio method on self-directed learning.This semi-empirical study conducted on 48 nursing students in medical-surgical ward. The sample was selected using census sampling method and classified into intervention and control groups. Data were collected using self-directed learning (SDL). Statistical analysis was performed using t-test, ANOVA, Kruskal-Wallis test, Chi-square and Pearson correlation coefficient with the help of SPSS-18.The intra-group comparison and total scores indicated the conventional teaching and portfolio methods increased the scores of self-control and self-management in both intervention and control groups. The intergroup comparison showed the same outcomes. So no statistically significant differences were observed. The total scores of self-directed learning showed the conventional teaching and portfolio methods will increase nursing students' self-directed learning (P=0.001 and P=0.003 for intervention and control groups, respectively). However, self-directed learning in intervention group showed a significant increase compared to the control group (P=0.006). It can be inferred that the conventional method has been able to strengthen self-direction in nursing students in the field internship and the homework assignments in the form of a portfolio will increase its impact on self-direction.