Abstract: Background and Objective: Root-knot nematode and Fusarium oxysporum f. sp. cucumerinum is one of the most damaging pests in polyhouse crops under protected conditions. Effective fumigants are needed for controlling these destructive pathogens in under protected conditions. The experiment was conducted under polyhouse conditions to study the effect of soil fumigants on the population of root-knot nematode and disease incidence (%) of the fungus on cucumber. However, till date there is very less work have been done on this aspect. Materials and Methods: Autoclaved sterilized soil inoculated with Meloidogyne incognita and Fusarium oxysporum f. sp. cucumerinum. Infested soil fumigated with formalin at 5, 10 and 30% and dazomet at 0.3, 0.6 and 0.9 g kg–1 soil for the management of both the pathogens. Chemical checks with Bavistin at 2 g L–1 water and carbofuran at 1 mg a.i. kg–1 soil, as well as untreated check, were also maintained. Results: The results revealed that all the fumigants were significantly improved plant growth parameters and reduced galling, egg masses formation, final nematode population (PF), reproduction factor (RF) and disease incidence (%) as compared untreated inoculated check. Conclusion: In the present study, results clearly indicated that fumigants have wide range of the nematicidal activity for the reducing nematode as well disease incidence (%).