Effects of Aspergillus niger was investigated on the strength of cotton textile specimens impregnated with nano-wollastonite, and then compared with normal specimens. Cotton strips were cut and prepared in warp and wept directions according to the standard specifications ASTM D-5035. Results showed that incubation of A. niger on specimens for three months resulted in a significant decrease in tensile stress as well as weight mass change in both directions. Impregnating specimens with NW ameliorated the negative effects of fungal attack on tensile stress to a considerable extent. Moreover, weight change was significantly decreased. It is concluded that NW positively protect cotton textile against A. nigra; the ultimate NW-content should be studied in complimentary studies.