Ergospirometry is a diagnostic procedure to continuously measure respiration and gas metabolism during ergometer exercise. It enables judgement of function and performance capacity of the cardiopulmonary system and metabolism. Ergospirometry is made up of the 2 components spirometry and ergometry. The first attempts to measure human gas metabolism while performing quantified physical work can be traced back to the year 1790. The development of procedures to measure gas metabolism and respiration as well as the construction of ergometers in the nineteenth and twentieth centuries are described.Ergospirometry and routinely performed clinical performance diagnosis were introduced in 1929, but it was not until the 1950s when the first ergospirometry apparatus which met all scientific requirements was developed. The parameters used and the physiological and pathophysiological findings by ergospirometry are given in an historical frame. Numerous medical fields have profited from the technique of ergospirometry, for example: cardiology, pneumology, sports medicine, exercise physiology, biochemistry, clinical pharmacology, surgery, orthopaedics, paediatrics and gerontology, besides such global disciplines as preventive medicine, exercise therapy and rehabilitative medicine.