We investigate the stability of positive stationary solutions of semilinear initial-boundary value problems with delay and convex or concave nonlinearity. If the nonlinearity is monotone, then in the convex case /(O) < 0 implies instability and in the concave case /(O) > 0 implies stability. Special cases are shown where the monotonicity assumption can be weakened or omitted. ©2001 Southwest Texas State University.