BACKGROUND: The choice of the right implant shape is one of the most frequent debates in cosmetic breast augmentation. In current literature, the question of whether there is a difference in the appearance of different implant shapes is still an argument of highly controversial discussion. The aim of the present work was, therefore, to analyze whether any difference exists in terms of aesthetic outcome between round and anatomical implants, and if they can be distinguished from each other in a like for like swap, making sure the evaluation was made in exactly similar conditions. METHODS: Fourteen consecutive patients who underwent aesthetic breast augmentations received primarily an implant of a given volume, projection, and shape (round or anatomical) and then decided to undergo implant replacement to a different shape but maintaining the same volume and projection. At 12-months follow-up, standardized photographs were taken, blinded and randomized. They were evaluated by 10 plastic surgeons and 10 nurses. RESULTS: All 20 observers could distinguish between round and anatomical shape in all 14 cases (100%), which was highly significant ( < 0.0001) for each observer. CONCLUSIONS: The present data indicate that there is a clear difference between anatomical and round-shaped implants in terms of aesthetic appearance, when a comparison is properly performed. With the use of both round and anatomical implant shapes, aesthetically appealing results can be achieved in cosmetic breast augmentation. The right implant choice must be made, based on patients' anatomy and desires.