<P> In 1966 , the Dallas Cowboys , who had been founded six years earlier , adopted the practice of hosting Thanksgiving games . It is widely rumored that the Cowboys sought a guarantee that they would regularly host Thanksgiving games as a condition of their very first one ( since games on days other than Sunday were uncommon at the time and thus high attendance was not a certainty ) . This is only partly true ; Dallas had in fact decided to host games on Thanksgiving by their own decision because there was nothing else to do or watch on that day . In 1975 and 1977 , at the behest of then - Commissioner Pete Rozelle , the St. Louis Cardinals replaced Dallas as a host team ( Dallas then hosted St. Louis in 1976 ) . Although the Cardinals , at the time known as the `` Cardiac Cards '' due to their propensity for winning very close games , were a modest success at the time , they were nowhere near as popular nationwide as the Cowboys , who were regular Super Bowl contenders during this era . This , combined with St. Louis 's consistently weak attendance , a series of ugly Cardinals losses in the three - game stretch , and opposition from the Kirkwood -- Webster Groves Turkey Day Game ( a local high school football contest ) led to Dallas resuming regular hosting duties in 1978 ; it was then , after Rozelle asked Dallas to resume hosting Thanksgiving games , that the Cowboys requested ( and received ) an agreement guaranteeing the Cowboys a spot on Thanksgiving Day forever . </P>
when did the cowboys start playing on thanksgiving day
1978