Abstract The ampulla-diver respirometer as described by Zajicek and Zeuthen [9, 10] is the most sensitive technique available for measurements of gaseous exchange in biological material. However, the micro-diver technique requires repeated and close manual manometrical adjustments by a trained person. In this report an automatic recording unit for the micro-diver technique is described. Minimal personal attendance in combination with gains in objectivity and frequency of the registrations are obvious advantages of importance. The possibility of variation of the sensitivity makes the system in addition suitable for recordings in the range of the standard diver .