Background: Minimally invasive techniques for open heart surgery are widely accepted in these days. There are minimally invasive approaches by the right or left parasternal incision and another approaches by mini-sternotomy of upper or lower half or sternum. We report the safety and efficacy of minimally invasive technique with right parasternal incision compared with the routine full sternotomy. Material and Method: From April 1997 through February 1999, 20 patients(Group A) underwent minimally invasive cardiac operations. We chose 41 patients(Group B) whose preoperative diagnosis were the same and general conditions were similar and who underwent routine full sternotomy before April 1997. We compared A group and B group in many aspects. We performed routine full median sternotomy in B group but we did a minimally invasive technique through a small right parasternal incision in A group. Result: mean age was 36.1 years in both groups. In disease entities, there were 11 cases of ASD, 9 cases of mitral valve disease in group A, and 16 cases of ASD, 25 cases of mitral valve diseases in group B. In ASD, operation time, cardiopulmonary bypass time of aortic occulusion time were 263 min, 82 min, and 41 min in group A and 180 min, 53 min, and 32 min in group B. In mitral valve disease, operation time, cardiopulmonary bypass time and aortic occlusion time were 267min, 106 min, and 70min in A group and were 207 min, 82 min, and 69 min in group B. There were significant differences in operation time, CPB time, and ACC time between group A and group B. There was a significant difference in the amount of bleeding in postoperative day 1 between group A and group B of mitral diasease. However, there was no significant difference in the amount of bleeding in other comparisons. Mean length of incision was 8.7 cm in group A. There was no significant difference in postoperative complications between A group and B group. There was no mortality in either group. Conclusion: We conclude that this minimally invasive technique with right parasternal incision is cosmetically excellent but it is not effective in reducing operative time and there was no significant difference in recovery time and postoperative complications compared with routine full sternotomy.