Objective To assess the side effects and the continuation rate of combined oral contraceptive (COC) containing desogestrel (Marvelon ) during 12 months. Methods This was a post-marketing surveillance study on Marvelon COC among 870 healthy rural women in 5 different counties of Jiangsu Province during 12 months. Results About 24.02% of the women who used Marvelon COC experienced side effects during 12 months. Gastrointestinal disorder, bleeding/spotting and chloasma were ranked the first three in the side effects. The rate of side effects of Marvelon COC users during the first 3 months in south area of Jiangsu was significantly higher than that of users in north area of Jiangsu. Most of the users did not experience obvious weight changes i.e., loss or increase in weight of more than 5 kg during 12 months. Blood pressure and biochemical indicators of almost 99% among users were within the normal range. The gross cumulative continuation rate for 12 months was 83.14%; the most common medical reason for discontinuation was gastrointestinal disorder. There was an increased risk of discontinuation use among women with lower educational level.Conclusion Marvelon COC brought fewer side effects and was well accepted when applied in Chinese rural women.