The invention relates to a system for estimating glucose in plasma, comprising: a sensor that generates a signal from a concentration of glucose measured in a medium, filtering means, and a glycemic estimator. The invention also relates to a method comprising the following steps consisting in: i) generating a signal that represents the concentration of glucose measured in the medium; ii) filtering the signal generated; iii) applying a set of local estimation models to the aforementioned signal, thereby obtaining a set of local glucose-in-plasma estimations; iv) applying a weighting to each of the local estimations obtained; v) estimating a concentration of glucose in plasma by adding together the weighted local estimations obtained in the previous step; and vi) correcting the signal obtained in the preceding step using blood sugar reference measurements, and obtaining the final glucose-in-plasma estimation.