In this paper we estimate a multiple - output generalization of Khaled's BOX -COX model to study the cost structure and growth in productivity in Egyptian Textile industry. The estimated model includes several commonly used some flexible functional forms as special or limiting cases. Total factor productivity is estimated parametrically rather than being computed as the residual of growth in outputs minus growth in inputs. These findings were robust across cost function specifications, casting some doubt on the importance of choosing among flexible functional forms.