diff --git a/src/YAFF/bond_mm3.cpp b/src/YAFF/bond_mm3.cpp
index a5ef6fb8bc..31ce2dad3e 100644
--- a/src/YAFF/bond_mm3.cpp
+++ b/src/YAFF/bond_mm3.cpp
@@ -31,7 +31,10 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-BondMM3::BondMM3(LAMMPS *lmp) : Bond(lmp) {}
+BondMM3::BondMM3(LAMMPS *lmp) : Bond(lmp)
+{
+  born_matrix_enable = 1;
+}
 
 /* ---------------------------------------------------------------------- */
 
@@ -219,3 +222,19 @@ double BondMM3::single(int type, double rsq,
   else fforce = 0.0;
   return k2[type]*dr2*(1.0+K3*dr+K4*dr2);
 }
+
+/* ---------------------------------------------------------------------- */
+
+void BondMM3::born_matrix(int type, double rsq, int /*i*/, int /*j*/, double &du, double &du2)
+{
+  double r = sqrt(rsq);
+  double dr = r - r0[type];
+  double dr2 = dr * dr;
+  double dr3 = dr2 * dr;
+
+  double K3 = -2.55 * k2[type] /force->angstrom;
+  double K4 = 7.0 * k2[type] * 2.55 * 2.55 / (12.0 * force->angstrom * force->angstrom);
+
+  du = 2.0 * k2[type] * dr + 3.0 * K3 * dr2 + 4.0 * K4 * dr3;
+  du2 = 2.0 * k2[type] + 6.0 * K3 * dr + 12.0 * K4 * dr2;
+}