diff --git a/doc/tex/Makefile b/doc/tex/Makefile
index bdb29dd07e..40f76fc965 100644
--- a/doc/tex/Makefile
+++ b/doc/tex/Makefile
@@ -24,7 +24,7 @@ ifeq ($(findstring fncychap.sty,$(shell find `$(KPATHSEA) --expand-braces='$${TE
 endif
 endif
 	@cp asterisk.tex asterisk.tex.orig
-	@sed -e 's/ASTERISKVERSION/$(shell echo $(ASTERISKVERSION) | sed -e 's/\//\\\//g')/' asterisk.tex > asterisk_local.tex
+	@sed -e 's/ASTERISKVERSION/$(shell echo $(ASTERISKVERSION) | sed -e 's/\//\\\//g' | sed -e 's/_/\\_/g')/' asterisk.tex > asterisk_local.tex
 	@mv asterisk_local.tex asterisk.tex
 	@$(RUBBER) --pdf asterisk.tex
 	@mv asterisk.tex.orig asterisk.tex