This study was aimed to develop morality improvement education program (MIEP) and to evaluate the effects of MIEP among nursing students by quasi experimental design. Theoretical framework is based on Ajzen’s theory of planned behavior and Rest's Four-Component Model: moral sensitivity, moral judgement, moral motivation, and moral implementation. Research design used a nonequivalent control group pre-post test. Participants were 75 undergraduate nursing students recruited from S college, assigned to either an experimental group (38 students) or a control group (37 students). The two hour education was provided once a week for eight weeks from March to June, 2013. Self-reported questionnaires were given to the students before and after the education. The data were analyzed using t-test, Chisquare-test, paired t-test, unpaired t-test, ANOVA, and MANCOVA with SPSS Windows 18.0 program. The results as follows: 1. The experimental group showed a more significant increase on the 4 components affecting morality improvement compared to the control group. 2. There was no significant differences on moral sensitivity and moral judgment between experimental group and control group. 3. The experimental group showed a more significant increase on moral motivation and moral implementation compared to the control group. Based on these results, this MIEP was effective in improving morality improvement, and especially increasing moral motivation and moral implementation among nursing students. MIEP developed in this study could be used for improving nursing students' morality.