Research compared of the differences audiologic results obtained between the Bone Anchored Hearing Aid (BAHA) of the preoperative test and the postoperative result with the BAHA positioned at the implanted abutment. Research conducted at Purpan hospital, Toulouse - France in 2010. Study conducted in 15 adults (11 females, 4 males), age from 52 years old to 73 years old The patients have hearing loss transmission or hearing loss mitex at the level ofthe average of the two ears. On the tonal audiometry, bone conduction hearing loss under 50dB at frequencies 500 Hz, 1000 Hz, 2000 Hz. On the speech audiometry, the listerning comprehension over 60 percent at intensity 45 dB to 50 dB. Resuls : On the tonal audiometry, the difference between measurements (BAHA of the preoperative test and the postoperative result) from 2 dB to 7.7 dB at the frequencies 250 Hz to 4000 Hz. Medium differencie is 4.4 dB, Delta: 1.95 dB, P 0.05. On the speech audiometry, the difference between measurements from 2.7 percent to 10 percent, Medium differencie is 3.9 percent, Delta: 3.28 percent, P 0.05.