This article reports the thermodynamics of Se58Ge42-xPbx (9 <= x <= 20) glassy alloys determined from the heat of fusion and specific heat capacity measurements. A differential scanning calorimetry method has been employed for the determination of thermodynamic quantities such as entropy, enthalpy, and Gibbs free energy differences between the glassy and crystalline phase of these alloys as a function of temperature. An effort has also been made to determine the stability of these glasses using the data obtained from different thermodynamic quantities. This Study reveals that stability of the samples increases with the increase of lead (Pb) content in the glassy alloys.