Density functional theory calculations based on the Kohn-Sham method are the method of choice if the electronic structure of large molecular or solid state systems is needed. Improvements in algorithms allow now the calculation of systems with many thousands of electrons on modern supercomputer. Going beyond these system sizes and at the same time adapt to truly massive parallel computers causes new challenges for the field. The problems discussed in this talk will be related to new parallel algorithms to reduce the scaling to linear in system size and removing memory and communication bottlenecks in algorithms based partly on replicated data. Finally, new methods dealing with non-local potentials needed in modern realizations of density functional theory will be demonstrated.