  A homogeneous knot is a generalization of alternating knots and positive
knots. We determine the Rasmussen invariant of a homogeneous knot. This is a
new class of knots such that the Rasmussen invariant is explicitly described in
terms of its diagrams. As a corollary, we obtain some characterizations of a
positive knot. In particular, we recover Baader's theorem which states that a
knot is positive if and only if it is homogeneous and strongly quasipositive.
