Superplastic deformation in compression has been performed on Al2O3-ZrO2 laminated composites with volume fractions of zirconia from 0 to 20%. In the as-sintered condition, the materials exhibit a fine-grained (0.2 mu m) microstructure, but show differences in residual porosity depending on the zirconia content. The grain boundary sliding (GBS) contribution is known to be the main mechanism of deformation in the superplastic regime. Its contribution to the total deformation can be obtained from the knowledge of the intragranular deformation and from the strain due to densification. The contribution of the intragranular deformation was estimated by two different methods, namely the measurement of the grain shape variation and the change in the crystallographic texture of alumina. The reliability of the two methods are discussed since some differences are observed. The higher GBS contribution in the materials which exhibit the lower residual porosity is also discussed.