Solar ponds both collect and store solar radiation into sensible heat in the same medium. In this study, salt gradient solar pond was constructed for making an experimental work at the Istanbul Technical University and a one-dimensional transient mathematical model was developed and presented. It is based on unsteady state heat conduction model with an internal heat generation. Energy balance equations for UCZ, NCZ and LCZ were written in terms of differential equations. These are solved numerically to predict the thermal performance of the pond. The comparison of temperature profiles showed that they are qualitatively in good agreement with the physics of the solar ponds.