In this work, we were interested in the modeling of syneresis of physical chitin hydrogels by a mathematic law allowing us to predict the variation of the weight of the gel as a function of time. The variation of the weight of the gel during syneresis can be described by W-t/W-u = (t(1/2) + (W-infinity/W-0)t)1(t(1/2)) + t) where W-0, W-infinity, and W, are the weights of the gel at the beginning of syneresis, for infinite Lime and for a time t, respectively. t(1/2) corresponds to the half-time of syneresis. W-infinity/W-U and t(1/2) were studied in relation with several parameters such as the ionic strength, pH, degree of acetylation of chitin and the initial concentration of polymer. The mechanical properties of chitin hydrogels maintained during syneresis in media of different pH's and ionic strengths were also investigated.