In order to know the sex expression modification of Luffa cyllndrica L. cropped at San Antonio del Tequendama (Colombia) the plants were treated with different dosis of GA 3 ' Ethrel and NAA. AII dosis of GA3 and Ethrel caused over two or three flowers of staminate inflorescence, the development of pistillate flower and latter were fertilized and they transformed to fruits. Whereas the NAA 10 ppm change the flowering pattern, namely of the pistillate flower which were inhibed and in their place an staminate inflorescence were developed. The sex expression modification took place at two, three or four nodes of the plants.