Rubber is a waste product produced by the industrial sector in large quantities. Due to its non-degradable nature, it has been a serious threat to the environment. Thus, it is recommended to develop concrete or mortar containing rubber, so that it can save our environment, and it is economical too. Crumb rubber, when incorporated in mortar, reduces its strength, so it can be used along with some fibers to enhance its strength. This study examined the effect of elevated temperatures, i.e., 150, 300, 450, 600, and 750 °C, on mortar samples containing 5% crumb rubber replacement of fine aggregate by volume, and with the incorporation of 1% PPF. The findings indicated a rise in compressive strength up to 300 °C, followed by a subsequent decline. It was also observed that the weight loss of the samples increased with an increase in temperature.