Two designs of sonotrode were investigated in which the tip of a 20 kHz ultrasonic horn was adapted for use as the working electrode, in a conventional three-electrode system, for sonoelectrochemical studies. The first consisted of a platinum disc embedded in the titanium alloy tip of the horn probe and the second merely of an untreated Ti alloy tip, used as suggested by Reisse et al.[14] Their performances were compared. The former showed high mass transport conditions and clean, reversible electrochemistry for a variety of model systems. The latter gave behaviour characteristic of the n-type semiconducting layer of TiO2 known to be present on the surface of metallic titanium.