Abstract.Let (x, r) e Rm x R and u e C2(Rm x R). We discuss local and microlocal analyticity for solutions u to the nonlinear equation ut = f(x, t, u, ux).Here f(x, /, fo . 0 's complex valued and analytic in all arguments. We also assume / to be holomorphic in (Co, C) € C x Cm . In particular we show that WF^ u c Char(/_") where WF^ denotes the analytic wave-front set and Char(L") is the characteristic set of the linearized operatorIf we assume u 6 C3(Äm x R) then we show that the analyticity of u propagates along the elliptic submanifolds of Lu .