A method for adaptation of an electrochemical gas sensor which is situated in an exhaust line from a combustion engine and comprises • a measuring chamber for receiving an amount of the exhaust gases which pass through the exhaust line, • measurement means for generating a measurement signal which depends on the concentration of a specific gas in said amount of exhaust gases and is converted by means of a signal processing algorithm to a value which represents the concentration of said gas in the exhaust gases, and • a temperature regulating means by which the temperature of said amount of exhaust gases can be regulated, characterised - in that sets of measured values are recorded at three or more different times during a period when the operating conditions of the engine are such that the composition of the exhaust gases released by it is maintained substantially unchanged, each of which sets of measured values comprises a first value (S 1) corresponding to the magnitude of said measurement signal at the time of the respective recording, and a second value (T 1) corresponding to the temperature of the amount of exhaust gases at the time of the respective recording, - that said temperature regulating means is controlled in such a way that the temperature of said amount of exhaust gases is different at the time of each recording during the relevant period, - that a value for one or more constants which form part of the signal processing algorithm is determined on the basis of the values (S i, T i) in said sets of measured values and in the light of relationships between these values which arise from the general gas law, and - that the gas sensor is adapted by adjustment of the signal processing algorithm according to the value determined for each constant. • a measuring chamber for receiving an amount of the exhaust gases which pass through the exhaust line, • measurement means for generating a measurement signal which depends on the concentration of a specific gas in said amount of exhaust gases and is converted by means of a signal processing algorithm to a value which represents the concentration of said gas in the exhaust gases, and • a temperature regulating means by which the temperature of said amount of exhaust gases can be regulated, - in that sets of measured values are recorded at three or more different times during a period when the operating conditions of the engine are such that the composition of the exhaust gases released by it is maintained substantially unchanged, each of which sets of measured values comprises a first value (S 1) corresponding to the magnitude of said measurement signal at the time of the respective recording, and a second value (T 1) corresponding to the temperature of the amount of exhaust gases at the time of the respective recording, - that said temperature regulating means is controlled in such a way that the temperature of said amount of exhaust gases is different at the time of each recording during the relevant period, - that a value for one or more constants which form part of the signal processing algorithm is determined on the basis of the values (S i, T i) in said sets of measured values and in the light of relationships between these values which arise from the general gas law, and - that the gas sensor is adapted by adjustment of the signal processing algorithm according to the value determined for each constant.