NAMD (Nanoscale Molecular Dynamics program, formerly Not Another Molecular Dynamics Program) is a freewaremolecular dynamics simulation package written using the Charm++ parallel programming model, noted for its parallel efficiency and often used to simulate large systems (millions of atoms). It has been developed by the joint collaboration of the Theoretical and Computational Biophysics Group (TCB) and the Parallel Programming Laboratory (PPL) at the University of Illinois at Urbana-Champaign.
It was introduced in 1995 by Nelson et al. as a parallel molecular dynamics code enabling interactive simulation by linking to the visualization code VMD. NAMD has since matured, adding many features and scaling to thousands of processors. The latest stable version (as of October 2014) is 2.10.
Both pre-compiled binaries and the source code of NAMD are available free of charge for non-commercial use by individuals, academic institutions and corporations for in-house business purposes.