1. An experimental study was conducted on two similar double slope solar stills, one with fins attached to the basin liner and one without fins. 2. It was observed that the daily distillate output from the finned basin solar still was 18% higher than the conventional double slope solar still without fins. 3. The addition of fins to the basin liner increased both daytime and nighttime productivity. The efficiency of the finned basin solar still was 20% higher than the conventional still without fins.