THE RATIO OF DECAY CONSTANTS F(B) F(D)

The result f(B) approximate to f(D), which had been obtained from sum rules and lattice calculations, and which contradicts the naive predic tion f(p) similar to 1/root M(p), is rederived using a simple argument based on semilocal parton-hadron duality. It is argued that both here and in sum rules the key point is the use of semilocal duality instea d of the bound-state wave functions.