diff --git a/pkgs/applications/science/molecular-dynamics/gromacs/default.nix b/pkgs/applications/science/molecular-dynamics/gromacs/default.nix
new file mode 100644
index 000000000000..c687fd5908c4
--- /dev/null
+++ b/pkgs/applications/science/molecular-dynamics/gromacs/default.nix
@@ -0,0 +1,46 @@
+
+{ stdenv, fetchurl, cmake,
+  singlePrec ? true,
+  fftw
+}:
+
+
+stdenv.mkDerivation {
+  name = "gromacs-4.5.5";
+
+  src = fetchurl {
+    url = "ftp://ftp.gromacs.org/pub/gromacs/gromacs-4.5.5.tar.gz";
+    md5 = "6a87e7cdfb25d81afa9fea073eb28468";
+  };
+
+  buildInputs = [cmake fftw];
+
+  cmakeFlags = ''
+    ${if singlePrec then "-DGMX_DOUBLE=OFF" else "-DGMX_DOUBLE=ON -DGMX_DEFAULT_SUFFIX=OFF"}
+  '';
+
+  meta = {
+    homepage    = "http://www.gromacs.org";
+    licence     = "GPLv2";
+    description = "The GROMACS molecular dynamics software package";
+    longDescription = ''
+      GROMACS is a versatile package to perform molecular dynamics,
+      i.e. simulate the Newtonian equations of motion for systems
+      with hundreds to millions of particles.
+
+      It is primarily designed for biochemical molecules like
+      proteins, lipids and nucleic acids that have a lot of
+      complicated bonded interactions, but since GROMACS is
+      extremely fast at calculating the nonbonded interactions (that
+      usually dominate simulations) many groups are also using it
+      for research on non-biological systems, e.g. polymers.
+
+      GROMACS supports all the usual algorithms you expect from a
+      modern molecular dynamics implementation, (check the online
+      reference or manual for details), but there are also quite a
+      few features that make it stand out from the competition.
+
+      See: http://www.gromacs.org/About_Gromacs for details.
+    '';
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index df5b806de85c..472b167247d2 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -8656,6 +8656,21 @@ let
 
   openblas = callPackage ../development/libraries/science/math/openblas { };
 
+
+  ### SCIENCE/MOLECULAR-DYNAMICS
+
+  gromacs = callPackage ../applications/science/molecular-dynamics/gromacs {
+    singlePrec = true;
+    fftw = fftwSinglePrec;
+    cmake = cmakeCurses;
+  };
+
+  gromacsDouble = lowPrio (callPackage ../applications/science/molecular-dynamics/gromacs {
+    singlePrec = false;
+    fftw = fftw;
+    cmake = cmakeCurses;
+  });
+
   ### SCIENCE/LOGIC
 
   coq = callPackage ../applications/science/logic/coq {