The resistance elicitor Benzothiadiazole (BTH) has no significant inhibitory effects on seed germination of cotton cultivars Giza 86 and Giza 90 or on mycelial growth of the tested fungi, i.e. Fusarium solani, F. oxysporum, F. moniliforme, Sclerotium rolfsii, Macrophomina phaseolina, Pythium sp. and Rhizoctonia solani. BTH seed treatment (seed soaking) resulted in resistant cotton plants against infection by all pathogenic fungi tested. Efficiency of BTH to induce resistance in cotton seedlings varied with BTH concentration and fungi tested. Increasing BTH concentration enhanced resistance capacity of cotton cultivars. In addition. When the concentration was increased to 100 ppm, BTH significantly increased plant height from 8.36 to 26.07 % and from 8.93 to 28.82 % for cvs. Giza 86 and Giza 90, respectively. Also, it increased dry weight from 2.87 to 53.26 % and from 9.85 to 31.16 % for cvs. Giza 86 and Giza 90, respectively. The highest efficiency value (60%) was achieved by BTH against F. oxysporum on Giza 86 and F. moniliforme on Giza 90 while the least efficiency was observed by BTH seed treated against Rhizoctonia solani infection. Since 50 ppm of BTH seed treatment caused 18.18 and 21.49% protection in cotton seedlings of cvs. Giza 86 and Giza 90, respectively. Using 100ppm of BTH gave cotton seedlings with 31.81 and 25.62 % protection for Giza 86 and Giza 90, respectively.