A wide variety of pistons are available for stapes surgery in otosclerosis. The objective of this work was to analyze the short-term and medium-term results of Soft-CliP® piston in primary stapes surgery and to compare it with a conventional prosthesis. The study was prospective, monocentric, randomized, based on efficiency of Soft-CliP® prosthesis (11 patients) versus Causse® Teflon prosthesis (9 patients) in otosclerosis surgery. Epidemiological data, treatment modalities, pure-tone audiometric results and outcome of patients were studied. Mean follow-up was 10 months. Soft-CliP® placement was statistically longer. The mean postoperative air-bone gap was within 10 dB in 73% and 67% of cases at 2 months and in 82% and 89% of cases at medium-term in Soft-CliP® and Teflon groups respectively. A statistically significant decrease in mean air-bone gap and for all frequencies was observed at 2 months and at medium term, with no difference between the 2 groups. The main result was the demonstration of the reliability and safety of Soft-CliP® prosthesis. With a new design, Soft-CliP® placement was easy. The biomechanics of ossicular chain should be better preserved, and the risk of incus erosion and necrosis decreased. A study on a larger population in the long-term would validate these results.