The present study investigates the effects of teaching activity-based integrative reading and writing on the amelioration of written language in the elementary school classroom. This study was conducted during the first semester in 2003. The subjects were 160, 6th year elementary school students. They were divided into two groups, control and experimental. Both the control group and the experimental group were composed of 80 students each. Each group was divided into three levels: high, intermediate, and low, on the basis of a diagnostic evaluation. All the subjects of the experimental group were integratively taught reading and writing of the English alphabet, words, phrases, sentences, and context, according to their level. All the subjects of the control group were discretely taught reading and writing according to their curriculum and level. They were also given a questionnaire of affective and psychomotor domains. Statistical analyses were performed to determine: (a) the difference of the control and experimental groups, (b) the difference between the control and experimental groups, (c) the difference of their level (high, intermediate, and low) of the control and experimental groups on reading and writing in the pre- and post- achievement tests, and (d) the difference of the level of the control and experimental groups on the affective and psychomotor domains such as interest, self-confidence, understanding, participation, and motivation of reading and writing in the pre- and post- achievement tests. The results of this study reveal that significantly higher scores on the written language were obtained in the experimental group. The difference between the control group and the experimental group was not significant at the beginning of the term. However, the difference was significant at the end of the term. It was also found that in the experimental group, interest was improved at the intermediate level. Self-confidence and understanding were improved at the intermediate and low levels, and participation was improved at the low level. It is recommended that researchers and teachers develop integrative materials of reading and writing more widely according to the level.