Sens. Frank R. Lautenberg of New Jersey and Dick Durbin of Illinois say products like dip and chew endanger players' health and send "a dangerous message" to young fans.
In a letter, the senators urged Baseball Commissioner Bud Selig and union chief Michael Weiner to agree to a ban in their next collective bargaining agreement. The current agreement expires in December.
Smokeless tobacco is banned in the minor leagues but not in the majors.
Union spokesman Greg Bouris said Tuesday he expects the issue to be discussed during collective bargaining talks. Rob Manfred, the league's executive vice president for labor relations, said the league is striving for a ban.