In the last decades, an extensive amount of experimental laboratory and field studies were conducted with different warm mix asphalt (WMA) technologies around the world. While good performance for the WMA mixtures has been reported, their use with polymer-modified asphalt binders is still creating a concern for some highway agencies. This paper summarizes the laboratory evaluation of one of those WMA products with a typical dense-graded polymer-modified asphalt mixture used in California and Nevada. The objective of this paper was to assess whether the investigated WMA additive negatively influence the outstanding performance and durability experienced by the state DOTs for the polymer-modified asphalt mixture. The WMA mixture was produced in the laboratory and compared to an HMA control mixture using identical aggregates, binder, and mix design. Overall, the presented results indicated that the use of the warm-mix additive at lower production and compaction temperatures resulted in a similar or better resistance to moisture damage, rutting, and fatigue cracking when compared to the conventional HMA. Preliminary calculations showed potential fuel savings as well as measurable energy savings and noteworthy reduction in CO2 emissions are anticipated with the use of the WMA additive compared to the conventional HMA.