Different root rot fungi, Alternaria solani Fusarium solani, F. oxysporum, Rhizoctonia solani, Sclerotium rolfsii, Macrophomina phaseolina and Pythium sp. were isolated from various vegetables, i.e. Cucumber, Cantaloupe, Tomato and Pepper grown in plastic houses under protected cultivation system and showing root rot and or damping-off disease symptoms. The tested antagonistic fungi were Trichoderma harzianum, T. Viride and T. hamatum, Bacillus subtilis, Pseudomonas fluorescens and Saccharomyces cerevisiae. The efficacy of Calcium chloride, Thyme oil and /or bio-agents as seed dressing against disease incidence was evaluated in pot experiments under artificially infested with vegetables root rot causal organisms under greenhouse conditions. All applied treatments reduced significantly root rot incidence at both pre-, and post-emergence growth stages of Cucumber, Cantaloupe, Tomato and Pepper plants comparing with untreated check control. The obtained results showed that combination treatments of Calcium chloride, Thyme oil with bio-agents reduced significantly root rot incidence of all grown vegetables comparing with the application of each of them alone. Obtained results, in the present study, lead to suggest that integration between salt or essential oil and bio-agents is considered an applicable, safe and cost-effective method for controlling such soil-borne diseases.