We consider the differential equationẋ(t) = f (x(t), x(t − r)) where the delay r = r(x(·)) is defined by the threshold condition´t t−r a(x(s),ẋ(s)) ds = ρ with a given ρ > 0. It is shown that if f and a are analytic functions, a is positive, then the globally defined bounded solutions are analytic.Suggested running head: Analyticity of solutions