For prevention of cardiovascular disease, we recommended increased fish intake for 50 middle-aged women and men of 40-83 years old at a three-month community-based health education program in an inland farming community. The effectiveness of the education program was evaluated by examining changes in serum lipids and serum fatty acid compositions. For comparison, we selected 48 men and women of 38-82 years old did not participated in the program. Before education, there was no significant difference in the dietary frequency of fish, meat, egg and dishes prepared with oil, mean values of serum lipids or serum fatty acid compositions except for saturated fatty acid, gamma-linolenic acid, dihomo-gamma-linolenic acid and alpha-linolenic acid. After three months, the frequency of fish intake of one or more times per day increased from 33% to 43% in the education group while the frequency of fish intake did not change in the control group. In the education group, serum n3 polyunsaturated fatty acid composition increased from 8.8% to 10.6%. This fatty acid increase was primarily observed in eicosapentaenoic acid and docosahexaenoic acid. The n3/n6 ratio increased from 0.21 to 0.31. In the control group, no change was observed in n3 polyunsaturated fatty acids. This study suggests that the community-based dietary education increased fish intake and serum n3 polyunsaturated fatty acids in women and men of 40 years old or older.