Field studies were conducted near Knoxville, TN in 2004 to evaluate the response of ‘Thermal Blue' a new heat tolerant Kentucky bluegrass hybrid to preemergence (PRE) and postemergence (POST) herbicide applications. Thermal Blue exhibited significant injury to all seven preemergence herbicides tested when applied at seeding; dithiopyr, oryzalin, oxadiazon, pendimethalin, prodiamine, quinclorac, and trifluralin. Quinclorac at 840 g ai ha^-1 showed the least injury (81 %) 25 weeks after treatment (WAT). Established Thermal Blue exhibited tolerance to ten postemergence ALS herbicides applied at 1 and 2X the normal use rates; bispyribac-sodium, chlorosulfuron, foramsulfuron, halosulfuron, imazapic, imazaquin, metsulfuron, rimsulfuron, sulfosulfuron, and trifloxysulfuron. Foramsulfuron and trifloxysulfuron at 87 g ai ha^-1 and 35 g ai ha^-1 showed 36 and 26% injury 5 WAT. However, at 10 WAT the greatest injury (7%) occurred with trifloxysulfuron at 36 g ai ha^-1. Established Thermal Blue also displayed excellent tolerance to four postemergence graminicides applied at 0.5, 1, and 2X normal use rates. Unacceptable injury (>15%) was observed with clethodim (1 and 2X) at 280 and 560 g ai ha^-1, fluazifop (2X) at 420 g ai ha^-1 and sethoxydim (2X) at 630 g ai ha^-1. However, at 10 WAT the greatest injury (14%) occurred with clethodim at 560 g ai ha^-1. Overall, Thermal Blue is very susceptible to preemergence herbicides and precaution should be used when applying these products at seeding. Thermal Blue has excellent tolerance to many postemergence herbicides; however manufacturers suggested use and application rates for Kentucky bluegrass apply and should be followed carefully.