A comparative experimental study of a box type solar cooker with two different cooking vessels was conducted, the first one conventional and the second one identical to the first in shape and volume but its external lateral surface provided with fins. Fins are shown to improve the heat transfer from the internal hot air of the cooker towards the interior of the vessel where the food to be cooked is placed. This reduces the cooking time considerably. The tests were carried out on the experimental platform of the Research Unit in Renewable Energies in Saharan Medium of Adrar, located at 27 degrees 53'N latitude and 0 degrees 17'W longitude in the Algerian Sahara. (c) 2007 Published by Elsevier Ltd.