Control of the plant diseases using chemicals is one of the most important issues for vegetable crops because of the accumulation of harmful residues of these chemicals sometimes causing serious problems for both human health and agroecosystems. Therefore, a field experiment was carried out during two successive winter years 2014 and 2015 on cabbage and cauliflower plants at Sakha Horticulture Research Station Farm, Kafr El-Sheikh Governorate, Egypt. Different effects of bio-control agent microorganisms and some essential oils on growth, yield, quality and reducing damping-off disease of cabbage and cauliflower plants were recorded. Seven treatments including Bacillus subtillus, Trichoderma harzianum, eucalyptus oil, spearmint oil, clove oil, Rizolex T50 (fungicide) and control were arranged in a randomized complete block design with three replicates. Results revealed significant differences among various growth attributes, total head yield (ton/fed) and head quality due to essential oils and microorganisms. Also, microorganisms and essential oils under field condition improved transplants survive and reduced the damping-off disease incidence as compared to untreated control. Moreover applying of Trichoderma harzianum and Eucalyptus oils seemed to be superior in improving vegetative growth, total head yield with large and heavier heads. As well as, using of clove oil, Trichoderma harzianum and Bacillus subtillus increased shelf life period and decreased cabbage head weight loss percentage, while the superior treatment of cauliflower was Trichoderma harzianum compared to control.