diff --git a/emacs-23.1-fontdpi.patch b/emacs-23.1-fontdpi.patch
new file mode 100644
index 0000000..5f9a70b
--- /dev/null
+++ b/emacs-23.1-fontdpi.patch
@@ -0,0 +1,44 @@
+diff -up emacs-23.1/src/xterm.c.fontdpi emacs-23.1/src/xterm.c
+--- emacs-23.1/src/xterm.c.fontdpi	2010-01-04 09:11:45.000000000 +0100
++++ emacs-23.1/src/xterm.c	2010-01-04 11:50:19.627777180 +0100
+@@ -10380,17 +10380,31 @@ x_term_init (display_name, xrm_option, r
+ 				     dpyinfo->visual, AllocNone);
+ 
+   {
+-    int screen_number = XScreenNumberOfScreen (dpyinfo->screen);
+-    double pixels = DisplayHeight (dpyinfo->display, screen_number);
+-    double mm = DisplayHeightMM (dpyinfo->display, screen_number);
+-    /* Mac OS X 10.3's Xserver sometimes reports 0.0mm.  */
+-    dpyinfo->resy = (mm < 1) ? 100 : pixels * 25.4 / mm;
+-    pixels = DisplayWidth (dpyinfo->display, screen_number);
+-    mm = DisplayWidthMM (dpyinfo->display, screen_number);
+-    /* Mac OS X 10.3's Xserver sometimes reports 0.0mm.  */
+-    dpyinfo->resx = (mm < 1) ? 100 : pixels * 25.4 / mm;
++    /* If we are using Xft, check dpi value in X resources.
++       It is better we use it as well, since Xft will use it, as will all
++       Gnome applications. If our real DPI is smaller or larger than the
++       one Xft uses, our font will look smaller or larger than other
++       for other applications, even if it is the same font name (monospace-10
++       for example). */
++    char *v = XGetDefault (dpyinfo->display, "Xft", "dpi");
++    double d;
++    if (v != NULL && sscanf (v, "%lf", &d) == 1)
++      dpyinfo->resy = dpyinfo->resx = d;
+   }
+ 
++  if (dpyinfo->resy < 1)
++    {
++      int screen_number = XScreenNumberOfScreen (dpyinfo->screen);
++      double pixels = DisplayHeight (dpyinfo->display, screen_number);
++      double mm = DisplayHeightMM (dpyinfo->display, screen_number);
++      /* Mac OS X 10.3's Xserver sometimes reports 0.0mm. */
++      dpyinfo->resy = (mm < 1) ? 100 : pixels * 25.4 / mm;
++      pixels = DisplayWidth (dpyinfo->display, screen_number);
++      mm = DisplayWidthMM (dpyinfo->display, screen_number);
++      /* Mac OS X 10.3's Xserver sometimes reports 0.0mm. */
++      dpyinfo->resx = (mm < 1) ? 100 : pixels * 25.4 / mm;
++    }
++
+   dpyinfo->Xatom_wm_protocols
+     = XInternAtom (dpyinfo->display, "WM_PROTOCOLS", False);
+   dpyinfo->Xatom_wm_take_focus
diff --git a/emacs.spec b/emacs.spec
index c95b1ec..c4ff76b 100644
--- a/emacs.spec
+++ b/emacs.spec
@@ -4,7 +4,7 @@ Summary: GNU Emacs text editor
 Name: emacs
 Epoch: 1
 Version: 23.1
-Release: 17%{?dist}
+Release: 18%{?dist}
 License: GPLv3+
 URL: http://www.gnu.org/software/emacs/
 Group: Applications/Editors
@@ -34,6 +34,10 @@ Patch7: emacs-23.1-scroll.patch
 Patch8: emacs-23.1-indian.patch
 # Fixed in upstream CVS
 Patch9: emacs-23.1-memmove.patch
+# Taken from upstream GIT repository
+# http://git.savannah.gnu.org/cgit/emacs.git/diff/src/xsettings.c?id=b3a25b88e82569f916712c635207c8bdd590e13b
+# rhbz#517272
+Patch10: emacs-23.1-fontdpi.patch
 
 Buildroot: %{_tmppath}/%{name}-%{version}-root
 BuildRequires: atk-devel, cairo-devel, desktop-file-utils, freetype-devel, fontconfig-devel, dbus-devel, giflib-devel, glibc-devel, gtk2-devel, libpng-devel
@@ -133,6 +137,7 @@ Emacs packages or see some elisp examples.
 %patch7 -p1 -b .scroll
 %patch8 -p1
 %patch9 -p1 -b .memmove
+%patch10 -p1 -b .fontdpi
 
 # install rest of site-lisp files
 ( cd site-lisp
@@ -404,6 +409,9 @@ alternatives --install %{_bindir}/etags emacs.etags %{_bindir}/etags.emacs 80 \
 %dir %{_datadir}/emacs/%{version}
 
 %changelog
+* Mon Jan  4 2010 Karel Klic <kklic@redhat.com> 1:23.1-18
+- Fixed rhbz#517272 - emacs-23.1 update shows fonts in double the normal size
+
 * Tue Dec  8 2009 Karel Klic <kklic@redhat.com> 1:23.1-17
 - Fixed rhbz#545398 - ETags messes up filenames