In order to investigate the effect of heterosis, some quantitative characteristics were determined in 53 single, triple and double hybrid melon genotypes compared with the parental lines and Galia F-1 hybrid as control. Within the framework of this research, the heterosis and heterobeltiosis ratios were calculated for hybrids with two, three and four parents for the following characteristics: seedling emergence, lengths of cotyledons and the hypocotyls; length and diameter of the main stem, node number, first female flowering, total and early yields; fruit weight, length and diameter, and total soluble solids (TSS). The highest heterobeltiosis (184.23%) and heterosis (184.55%) rates were produced in earliness by Special Combination (SC)-58 (G22 X C1) genotypes belonging to the single hybrid group. Furthermore, superiority of the single hybrid group was observed both in total yield and in earliness of yield. Plant development criteria were also found better in single hybrid melon group.