To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (i.e. Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures were employed. Results of the evaluation were used to quantify the effect of CRM source and CRM content on engineering properties at testing temperatures of 25 ℃ and 60 ℃. Statistical models were developed, which represent the nature of effects on performance-related properties of stone matrix asphalt mixtures. To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (ie Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures were employed. Results of the evaluation were used to quantify the effect of CRM source and CRM content on engineering properties at testing temperatures of 25 ° C and 60 ° C Statistical Models were developed, which represent the nature of effects on performance-related properties of stone matrix asphalt mixtures.