Dilaton Supersymmetry Breaking

We argue that dilaton supersymmetry breaking in string derived supergravity requires an effective superpotential which is not separable as a function of the dilaton times a function of the moduli. We show that in a simple model with hidden sector matter condensation and a dilaton independent term one can easily obtain $|F_S| \not=0$. For a wide range of realistic model parameters $|F_S|>>|F_T|$ and supersymmetry is mainly broken in the dilaton direction.