The deformation of dispersed droplets in immiscible polymer blends was studied in elongational flow by means of an original method based on quenching specimens elongated in the melt. Results for nearly Newtonian phases at high capillarity numbers were found to be in good agreement with the predictions of the small deformation Newtonian theory, up to relatively high drop deformations. The linear theory could be generalized to viscoelastic phases, using Palierne’s theory of viscoelastic emulsions. The description of some experimental data could be improved in this way, but discrepancies due to nonlinear effects remained. Numerical simulations were carried out for different capillarity numbers in the Newtonian case and were in good agreement with experimental data. Preliminary results were also obtained for viscoelastic constitutive equations.