Cotton textiles are rare and rarely found in museums. In the presence of such textiles in uncontrolled museums condition , they are more vulnerable to damage by heat, humidity, insects, microorganisms "bacteria, fungi" , This study presents the results of study of one of the most dangerous factors damage to cellulosic textile "cotton", microorganisms "fungi" In the presence of accelerated artificial aging, , The study dealt with the impact of fungal stains and thermal aging on the mechanical properties and chemical composition of cotton fibers, Where many tests and analysis were carried out scanning electron microscope (SEM), USB Microscope , stereo microscope, and Fourier transform infrared spectral analysis (FTIR), In addition to some mechanical and physical tests such as measuring tensile strength and color change of samples by CIE-Lab values.