The impoverishment of our planet in non-renewable energies has incited researchers to design salinity gradient solar ponds to collect and store solar energy at a lower cost. It is in this context that the present research work lies to focus on the numerical study of the transient hydrodynamic, heat and mass transfer in a salinity gradient solar pond. The problem is tackled using the dimensionless governing equations of Navier-Stokes, thermal energy and mass transfer, which are solved numerically by finite-volume method to provide the temperature, concentration and velocity fields in transient regime. The pond is filled with salty water of various salinities to form three zones of salty water: Upper Convective Zone (UCZ), Non-Convective Zone (NCZ) and Lower Convective Zone (LCZ). To prevent convective movements induced by the internal heating of salty water due to solar radiation absorption, a salinity gradient is used in the solar pond. Representative results illustrating the influence of internal Rayleigh number on the thermal performance of the pond and the effect of the aspect ratio on the distribution of temperature and velocity fields in the salinity gradient solar pond (SGSP) are discussed. In addition, results for the transient average temperature of UCZ and LCZ are presented and discussed for various parametric conditions. (C) 2014 Elsevier Ltd. All rights reserved.