The experiments were conducted on watermelon (Citrullus lanatus L.) at an a private farm in Awlad Amr village, Qena city, Qena, Egypt located between 26° 10′ 0″ N, 32° 43′ 0″ E during the two consecutive spring-summer seasons of 2018 and 2019 respectively to study the effect of three different genotypes used as rootstocks on plant growth performance, fruit yield and quality of three watermelon F₁ hybrids. Tongue approach grafting method was used, three hybrids of watermelon which growing on a large scale of the commercial production of watermelons in Egypt namely, Aswan F₁, Misr1 F₁ and Star F₁ was grafted onto three different genotype rootstocks i.e. Cobalt F₁, Ferro F₁ and New Star F₁. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Calculated data revealed that, there are clear significant differences between the grafted and non-grafted plants. Results of yield characteristics and its component, such as fruit weight, fruits length and circumferences and total fruit yield per feddan (ton) (feddan = 0.420 hectares = 1.037 acres), indicated to the superiority of the Misr 1 F₁ hybrid which grafted onto Cobalt F₁ rootstock, followed by the Aswan F₁ when grafted onto Cobalt F₁ rootstock. On the other side, Ferro F₁ rootstock was poorly adapted with the all commercial hybrids of watermelon under studies.