Disclosed are hot melt adhesives comprising tackifier and a high M.sub.w, narrow MWD, narrow CD ethylene/alpha-olefin copolymer(s) and a low M.sub.w, narrow MWD, narrow MWD ethylene/alpha-olefin copolymer prepared with either supported or unsupported cyclopentadienyl derivatives of Group IV and catalysts for applications in hot melt adhesives, particularly in automotive product assembly, packaging and food packaging. These ethylene copolymers have a M.sub.w ranging from about 20,000 to about 100,000, an MWD of less than 6 and 3 to 17 mole percent comonomer, and composition distribution breadth index above 70 percent. These ethylene copolymer blends have a M.sub.w ranging from about 20,000 to about 100,000 and an MWD of less than 6. In addition, the copolymer blends have comonomer mole percent ranging from about 3 to about 17.