Abstract: Background and Objective: A comparative study was carried out on the effect of phytohormone on seed germination, seedling vigour and the phytochemical content of three cucurbits, which are Cucumis melo (L.), Lagenaria breviflora (Benth) and Citrullus lanatus (Thunb). Phytochemical analysis of air-dried, powdered epicarp, mesocarp and seeds of the mature fruits were carried out, also the effects of varying concentrations of indole acetic acid (IAA), naphthalene acetic acid (NAA) and gibberellic acid (GA3) on germination and seedling vigour of these 3 cucurbits were investigated. The study is designed to obtain the inhibitory and the stimulatory effects of the 3 cucurbits used in this research. Materials and Methods: Treatments were arranged in 5 replicates and monitored for 16 days. Experiments were carried out in 9 cm petri dishes in the laboratory. Data were subjected to two-way analysis of variance (ANOVA) at p<0.05. Means were compared using LSD. Results: The study revealed that the mean percentage germination and seedling vigour of Cucumis melo (C. melo) was significantly higher (p<0.05) in the control than in 100-500 ppm concentrations of GA3, IAA and NAA. Phenol was not detected in the epicarp and mesocarp of C. lanatus and seeds of L. breviflora. However, concentrations of phenol detected in the different parts of C. melo and Lagenaria breviflora (L. breviflora) (epicarp, mesocarp and seed) were not significantly different. The concentrations of the phytochemicals were significantly (p<0.05) different among the epicarp, mesocarp and seeds of the cucurbits except for alkaloid. However, concentrations of phenol detected in the different parts of C. melo and L. breviflora were not significantly different (p>0.05). Tannin was not detected in the epicarp, mesocarp and seeds of the three cucurbits. Flavonoid was also significantly higher (p<0.05) in the epicarp of C. melo and L. breviflora than in their mesocarp and seeds. Conclusion: Conclusively, effects of varying concentrations of IAA, NAA and GA3 was not significant on the parameters studied. Phytochemicals were detected in the epicarp, mesocarp and seeds of the cucurbits under investigation. This study revealed the phytochemical contents and the effects of hormones on the germination of seeds including the vitality of the seed produced.