In this paper, we study the notion of approximately bi at Banach algebras for second dual Banach algebras and semigroup algebras. We show that for a locally compact group G, if S(G) is approximately bi at, then G is an amenable group. Also we give some conditions which the second dual of a Triangular Banach algebra is never approximately bi at. For a uniformly locally nite semigroup S, we show that ℓ1(S) is approximately bi at if and only if ℓ1(S) is biflat.
