diff --git a/lib/Makefile.mk b/lib/Makefile.mk
index 791921a..ea471e0 100644
--- a/lib/Makefile.mk
+++ b/lib/Makefile.mk
@@ -19,6 +19,7 @@ SubDirs += interception
 SubDirs += profile
 SubDirs += sanitizer_common
 SubDirs += tsan
+SubDirs += ubsan
 
 # FIXME: We don't currently support building an atomic library, and as it must
 # be a separate library from the runtime library, we need to remove its source
diff --git a/lib/ubsan/Makefile.mk b/lib/ubsan/Makefile.mk
new file mode 100644
index 0000000..5702e0e
--- /dev/null
+++ b/lib/ubsan/Makefile.mk
@@ -0,0 +1,23 @@
+#===- lib/ubsan/Makefile.mk ---------------------------------*- Makefile -*--===#
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+
+ModuleName := ubsan
+SubDirs :=
+
+Sources := $(foreach file,$(wildcard $(Dir)/*.cc),$(notdir $(file)))
+ObjNames := $(Sources:%.cc=%.o)
+
+Implementation := Generic
+
+# FIXME: use automatic dependencies?
+Dependencies := $(wildcard $(Dir)/*.h)
+Dependencies += $(wildcard $(Dir)/../sanitizer_common/*.h)
+
+# Define a convenience variable for all the ubsan functions.
+UbsanFunctions := $(Sources:%.cc=%)
diff --git a/lib/ubsan/ubsan_value.h b/lib/ubsan/ubsan_value.h
index a855791..0c755ca 100644
--- a/lib/ubsan/ubsan_value.h
+++ b/lib/ubsan/ubsan_value.h
@@ -14,9 +14,9 @@
 #ifndef UBSAN_VALUE_H
 #define UBSAN_VALUE_H
 
-// For now, only support linux. Other platforms should be easy to add, and
-// probably work as-is.
-#if !defined(__linux__)
+// For now, only support linux and darwin. Other platforms should be easy to
+// add, and probably work as-is.
+#if !defined(__linux__) && !defined(__APPLE__)
 #error "UBSan not supported for this platform!"
 #endif
 
diff --git a/make/platform/clang_darwin.mk b/make/platform/clang_darwin.mk
index 6dc31d5..39e4951 100644
--- a/make/platform/clang_darwin.mk
+++ b/make/platform/clang_darwin.mk
@@ -76,6 +76,9 @@ UniversalArchs.asan_osx := $(call CheckArches,i386 x86_64,asan_osx)
 Configs += asan_osx_dynamic
 UniversalArchs.asan_osx_dynamic := $(call CheckArches,i386 x86_64,asan_osx_dynamic)
 
+Configs += ubsan_osx
+UniversalArchs.ubsan_osx := $(call CheckArches,i386 x86_64,ubsan_osx)
+
 #UniversalArchs.ios += $(call CheckArches,armv7f armv7k armv7s,ios)
 #UniversalArchs.cc_kext += $(call CheckArches,armv7f armv7k armv7s,cc_kext)
 #UniversalArchs.cc_kext_ios5 += $(call CheckArches,armv7f armv7k armv7s,cc_kext_ios5)
@@ -125,6 +128,8 @@ CFLAGS.asan_osx_dynamic := \
 	$(CFLAGS) -mmacosx-version-min=10.5 -fno-builtin \
 	-DMAC_INTERPOSE_FUNCTIONS=1
 
+CFLAGS.ubsan_osx	:= $(CFLAGS) $(OSX_DEPLOYMENT_ARGS)
+
 CFLAGS.ios.i386		:= $(CFLAGS) $(IOSSIM_DEPLOYMENT_ARGS)
 CFLAGS.ios.x86_64	:= $(CFLAGS) $(IOSSIM_DEPLOYMENT_ARGS)
 CFLAGS.ios.armv7	:= $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
@@ -177,6 +182,8 @@ FUNCTIONS.asan_osx_dynamic := $(AsanFunctions) $(InterceptionFunctions) \
                               $(SanitizerCommonFunctions) \
 	                      $(AsanDynamicFunctions)
 
+FUNCTIONS.ubsan_osx := $(UbsanFunctions)
+
 CCKEXT_COMMON_FUNCTIONS := \
 	absvdi2 \
 	absvsi2 \