diff --git a/src/msspec/spec/fortran/eig/common/eig_mat_ms.f b/src/msspec/spec/fortran/eig/common/eig_mat_ms.f
index 03ee7e7..06896f2 100644
--- a/src/msspec/spec/fortran/eig/common/eig_mat_ms.f
+++ b/src/msspec/spec/fortran/eig/common/eig_mat_ms.f
@@ -178,6 +178,10 @@ CKMD          WRITE(IUO1,*) '                        '
 CKMD          WRITE(IUO1,*) '    --->  WORK(1),INFO =',WORK(1),INFO
 CKMD          WRITE(IUO1,*) '                        '
 CKMD      ENDIF
+C
+CKMD Save eigenvalues to unformatted stream file eigenvalues.dat
+C
+      call save_eigenvalues(w, jlin, e_kin)
 C
       N_EIG=0
 C
diff --git a/src/msspec/spec/fortran/eig/common/save_eigenvalues.f b/src/msspec/spec/fortran/eig/common/save_eigenvalues.f
new file mode 100644
index 0000000..0824c4b
--- /dev/null
+++ b/src/msspec/spec/fortran/eig/common/save_eigenvalues.f
@@ -0,0 +1,37 @@
+c
+c=======================================================================
+c
+      subroutine save_eigenvalues (evalues, n, ke)
+c
+      implicit none
+c
+      integer,    intent(in) :: n
+      real,       intent(in) :: ke
+      complex*16, intent(in) :: evalues(n)
+c
+c Local variables
+c
+      integer :: io
+      logical :: exists
+c
+c
+      inquire(file='eigenvalues.dat', exist=exists)
+c
+      if (exists) then
+         open(newunit=io, file='eigenvalues.dat', status='old',
+     +        form='unformatted', access='stream', action='write',
+     +        position='append')
+      else
+         open(newunit=io, file='eigenvalues.dat', status='new',
+     +        form='unformatted', access='stream', action='write')
+      end if
+c
+      write(io) ke, n, evalues(1:n)
+c
+      close(io)
+c
+      return
+      end subroutine save_eigenvalues
+c
+c=======================================================================
+c