The aim of this study was to compare oval and round window vibroplasty. Eighteen (18) patients implanted with Vibrant Soundbridge (VSB) were enrolled. Two groups were formed depending on FMT placement: on round window in ten cases (RW group) and on oval window in eight (OW group). Pre and postoperative audiological tests were performed both under headphones and free-field settings, VSB on and off. One (1) RW patient experienced sudden hearing loss at the operated side after 4 months from surgery and was excluded from the analysis. Both groups showed good hearing results. Significant differences were measured at free-field pure-tone test with VSB on at 0.5 kHz (RW better than OW, p = 0.026) and 4 kHz (OW better than RW, p = 0.043). Both techniques share similar good results and are considered safe. However, we had one failure with deep and sudden hearing threshold worsening after some months of good results. From a surgical point of view OW vibroplasty is easier and safer to perform, when the stapes suprastructure is absent, as it does not require any drilling and should be preferred in such cases. More reports are needed to explain if RW vibroplasty is risky in a mid to long term.