The purposes of this study were to identify the effect of structured patient education on side effects and self care behaviors, and to find the strategy to promote their self care behavior. This study was a quasi-experimental(nonequivalent control pretest-posttest design) study and the subjects of this study consisted of 50(experimenal group 25, control group 25) patients hospitalized in K university hospital in Pusan. The data were collected from Oct, 1. to Oct, 31. 1997. The analysis of the collected data had been done for the homogeneity test in which general characteristics of experimental group and control group was tested by $x^2-test$ and the homogeneity test of side effects and self care behaviors by $x^2-test$ and t-test. To test the hypothesis, $x^2-test$ and t-test was given for degree of side effects and self care behaviors between the two groups. The results of this study were as follows: 1. The 1st hypothesis "The experimental group which had received the structured education should be different from the control group on the number of side effects" was rejected(p> .05). 2. The 2nd hypothesis "The experimental group which had received the structured education should be different from the control group on the severity of side effects" was rejected(P> .05). 3. The 3rd hypothesis "The experimental group which l)ad received the structured education should be different from the control group on the number of self care" was rejected(P> .05). 4. The 4th hypothesis "The experimental group which had received the structured education should be different from the control group on the degree of self care" was supported.(P<.001). In conclusion the patients who received the structured patient education showed increased in the degree of self care behaviors, so patient education is the effective nursing intervention to improve their self care behavior, further research is needed to find other factors to increase self care behavior undergoing chemotherapy.