An experimental study was conducted on new designs of basin type solar stills. Several single and double slope stills were constructed. Tests were conducted to show the effect of some modifications on the performance, such as productivity and efficiency. The modifications examined included preheating of feed water by means of a solar heater and utilizing external and internal condensers for vapor condensation as well as for feed water preheating. The results showed improvements in the output and efficiency of the solar stills due to the employment of the above modifications.