Method for determining the total mass of an automotive vehicle on the basis of data of a communication network, and of parameters of the vehicle, in which: - data are retrieved from a database of parameters of the vehicle, which parameters are hosted in a computer of the automotive vehicle, characterized in that it comprises the following steps: - setting parameters are retrieved from a settings database, included in the group comprising the execution time of the method for estimating the mass (ΔT), the covariance matrix of the measurement noise, the covariance matrix of the modelling indeterminacies with regard to the speed and the slope and the covariance matrix ( Q M) of the modelling indeterminacies with regard to the mass, - data originating from the communication network are retrieved, included in the group comprising the speed of the vehicle ( v), the downshift ratio of the transmission (γ), the level of depression of the brake pedal, the level of use of the retarder and an estimation of the torque provided by the heat engine ( T e) and of these mechanical frictions, - the motive force ( F t (t)) generated by the vehicle is determined as a function of the motor torque value ( T e), of the downshift coefficient of the transmission (γ), of the efficiency coefficient of the transmission (η gb) and of the radius of the wheel ( r w), - the aerodynamic friction force ( F a (t)) is determined as a function of the data retrieved from the database of parameters, - the rolling resistance force ( F r (t)) is determined as a function of the mass of the vehicle ( m v), of the coefficient of rolling resistance of the tyres ( c r), and of the slope of the road ( α), - the force induced by gravity ( F g ( t)) is determined as a function of the mass of the vehicle ( m v), of the gravity constant (g) and of the slope of the road ( α), and - an estimation of the total laden mass ( m v, est) of the vehicle, of the speed of the vehicle ( v est) and of the slope of the road ( α est) is determined at an instant (k) by applying the fundamental equation of dynamics and as a function of the values of the total mass of the vehicle, of the speed of the vehicle and of the slope of the road at a previous instant (k-1) in which in order to determine an estimation of the total laden mass (m v,est) of the vehicle, of the speed of the vehicle ( v est) and of the slope of the road ( α est), first so-called "Kalman" filter allowing the filtering of the speed of the vehicle and of the slope of the road and a second so-called "Kalman" filter making it possible to estimate the mass of the vehicle are applied, the two filters being applied in parallel and in which, at the same time as the step of determining an estimation of the total laden mass ( m v, est) of the vehicle, of the speed of the vehicle ( v est) and of the slope of the road ( α est), an estimation is determined of two covariance matrices, of dimension 2x2, expressing the covariance of the error in the speed variable and slope variable and ( P M) of dimension 1x1, expressing the covariance of the error in the mass variable as a function of the covariance matrix of the modelling indeterminacies with regard to the speed and the slope and of the covariance matrix ( Q M) of the modelling indeterminacies with regard to the mass on the basis of the fundamental equations of dynamics, of the values of the total mass of the vehicle, of the speed of the vehicle and of the slope of the road at a previous instant and of a Riccati equation whose sought-after variable is the covariance matrix of the estimation errors. - data are retrieved from a database of parameters of the vehicle, which parameters are hosted in a computer of the automotive vehicle, - setting parameters are retrieved from a settings database, included in the group comprising the execution time of the method for estimating the mass (ΔT), the covariance matrix of the measurement noise, the covariance matrix of the modelling indeterminacies with regard to the speed and the slope and the covariance matrix ( Q M) of the modelling indeterminacies with regard to the mass, - data originating from the communication network are retrieved, included in the group comprising the speed of the vehicle ( v), the downshift ratio of the transmission (γ), the level of depression of the brake pedal, the level of use of the retarder and an estimation of the torque provided by the heat engine ( T e) and of these mechanical frictions, - the motive force ( F t (t)) generated by the vehicle is determined as a function of the motor torque value ( T e), of the downshift coefficient of the transmission (γ), of the efficiency coefficient of the transmission (η gb) and of the radius of the wheel ( r w), - the aerodynamic friction force ( F a (t)) is determined as a function of the data retrieved from the database of parameters, - the rolling resistance force ( F r (t)) is determined as a function of the mass of the vehicle ( m v), of the coefficient of rolling resistance of the tyres ( c r), and of the slope of the road ( α), - the force induced by gravity ( F g ( t)) is determined as a function of the mass of the vehicle ( m v), of the gravity constant (g) and of the slope of the road ( α), and - an estimation of the total laden mass ( m v, est) of the vehicle, of the speed of the vehicle ( v est) and of the slope of the road ( α est) is determined at an instant (k) by applying the fundamental equation of dynamics and as a function of the values of the total mass of the vehicle, of the speed of the vehicle and of the slope of the road at a previous instant (k-1)