diff --git a/include/grpc/support/cpu.h b/include/grpc/support/cpu.h
index 005c3c721cc9965c1a3543fdfd180a7f4c42bdb2..2b2a56168aca58a9f6d176430c9c9b4879685922 100644
--- a/include/grpc/support/cpu.h
+++ b/include/grpc/support/cpu.h
@@ -41,7 +41,7 @@ extern "C" {
 /* Interface providing CPU information for currently running system */
 
 /* Return the number of CPU cores on the current system. Will return 0 if
-   if information is not available. */
+   the information is not available. */
 unsigned gpr_cpu_num_cores(void);
 
 /* Return the CPU on which the current thread is executing; N.B. This should
diff --git a/include/grpc/support/port_platform.h b/include/grpc/support/port_platform.h
index 1b613dc2fd76675fc541baef7282658aa9e71ec9..9b639cf82deef09dff160cf8d79c067bc0e95bb8 100644
--- a/include/grpc/support/port_platform.h
+++ b/include/grpc/support/port_platform.h
@@ -124,10 +124,15 @@
 #define GPR_ARCH_32 1
 #endif /* _LP64 */
 #elif defined(__APPLE__)
+#include <TargetConditionals.h>
 #ifndef _BSD_SOURCE
 #define _BSD_SOURCE
 #endif
+#if TARGET_OS_IPHONE
+#define GPR_CPU_IPHONE 1
+#else /* TARGET_OS_IPHONE */
 #define GPR_CPU_POSIX 1
+#endif
 #define GPR_GCC_ATOMIC 1
 #define GPR_POSIX_LOG 1
 #define GPR_POSIX_MULTIPOLL_WITH_POLL 1
@@ -185,8 +190,8 @@
 #error Must define exactly one of GPR_ARCH_32, GPR_ARCH_64
 #endif
 
-#if defined(GPR_CPU_LINUX) + defined(GPR_CPU_POSIX) + defined(GPR_WIN32) != 1
-#error Must define exactly one of GPR_CPU_LINUX, GPR_CPU_POSIX, GPR_WIN32
+#if defined(GPR_CPU_LINUX) + defined(GPR_CPU_POSIX) + defined(GPR_WIN32) + defined(GPR_CPU_IPHONE) != 1
+#error Must define exactly one of GPR_CPU_LINUX, GPR_CPU_POSIX, GPR_WIN32, GPR_CPU_IPHONE
 #endif
 
 #if defined(GPR_POSIX_MULTIPOLL_WITH_POLL) && !defined(GPR_POSIX_SOCKET)
diff --git a/src/core/support/cpu_iphone.c b/src/core/support/cpu_iphone.c
new file mode 100644
index 0000000000000000000000000000000000000000..d412a6d7ee6013922db6c7e3a6c81b8bce026e86
--- /dev/null
+++ b/src/core/support/cpu_iphone.c
@@ -0,0 +1,53 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_CPU_IPHONE
+
+/* Probably 2 instead of 1, but see comment on gpr_cpu_current_cpu. */
+unsigned gpr_cpu_num_cores(void) {
+  return 1;
+}
+
+/* Most code that's using this is using it to shard across work queues. So
+   unless profiling shows it's a problem or there appears a way to detect the
+   currently running CPU core, let's have it shard the default way.
+   Note that the interface in cpu.h lets gpr_cpu_num_cores return 0, but doing
+   it makes it impossible for gpr_cpu_current_cpu to satisfy its stated range,
+   and some code might be relying on it. */
+unsigned gpr_cpu_current_cpu(void) {
+  return 0;
+}
+
+#endif /* GPR_CPU_IPHONE */
diff --git a/src/core/support/cpu_posix.c b/src/core/support/cpu_posix.c
index 5f45fb0bc36986e8ba7d4e01641359be30b3602d..99484e37fbc87bfd2b26abcce8aef64fe01d68e3 100644
--- a/src/core/support/cpu_posix.c
+++ b/src/core/support/cpu_posix.c
@@ -74,4 +74,4 @@ unsigned gpr_cpu_current_cpu(void) {
   return shard_ptr(&magic_thread_local);
 }
 
-#endif /* GPR_CPU_LINUX */
+#endif /* GPR_CPU_POSIX */