Abstract: An automated dissolution system (AUTO DISS) in which all operating steps are carried out synchronously is described. All steps from the filling of vessels with dissolution medium to cleaning and drying of vessels are controlled by a microcomputer. Up to 20 cycles can be tested in succession with six individual tablets per cycle. Online determination of active ingredient concentration. is possible with the aid of an integrated automatic sampler in combination with various measuring instruments such as UV - vis spectrometry, liquid chromatography or flow injection analysis. The suitability of the system was demonstrated by the dissolution and determination of brotizolam tablets and bepafant capsules using flow injection analysis and diode-array spectroscopy, respectively. Dissolution testing of solid oral dosage forms plays a very important part both in the development of new products and in quality control. A fully automated system for dissolution testing known as AUTO DISS is presented and its components are described. Online determination of active ingredient concentration is possible with the aid of an integrated automatic sampler in combination with various measuring instruments (UV-vis spectrometry, liquid chromatography and flow injection analysis). The suitability of the system is demonstrated by determination of the dissolution of brotizolam from tablets by FIA and of bepafant from capsules by diode-array spectroscopy.