diff --git a/webrtc/base/bytebuffer.cc b/webrtc/base/bytebuffer.cc
index 9730ff23d6..c2ffe60934 100644
--- a/webrtc/base/bytebuffer.cc
+++ b/webrtc/base/bytebuffer.cc
@@ -10,7 +10,6 @@
 
 #include "webrtc/base/bytebuffer.h"
 
-#include <assert.h>
 #include <string.h>
 
 #include <algorithm>
diff --git a/webrtc/base/fileutils.cc b/webrtc/base/fileutils.cc
index d354dd8eb5..ae9309ce1b 100644
--- a/webrtc/base/fileutils.cc
+++ b/webrtc/base/fileutils.cc
@@ -8,11 +8,11 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include <assert.h>
+#include "webrtc/base/fileutils.h"
 
 #include "webrtc/base/arraysize.h"
+#include "webrtc/base/checks.h"
 #include "webrtc/base/pathutils.h"
-#include "webrtc/base/fileutils.h"
 #include "webrtc/base/stringutils.h"
 #include "webrtc/base/stream.h"
 
@@ -112,7 +112,7 @@ std::string DirectoryIterator::Name() const {
 #if defined(WEBRTC_WIN)
   return ToUtf8(data_.cFileName);
 #else
-  assert(dirent_ != NULL);
+  RTC_DCHECK(dirent_);
   return dirent_->d_name;
 #endif
 }
diff --git a/webrtc/base/firewallsocketserver.cc b/webrtc/base/firewallsocketserver.cc
index bf3ec42433..d6d03df3ad 100644
--- a/webrtc/base/firewallsocketserver.cc
+++ b/webrtc/base/firewallsocketserver.cc
@@ -10,11 +10,10 @@
 
 #include "webrtc/base/firewallsocketserver.h"
 
-#include <assert.h>
-
 #include <algorithm>
 
 #include "webrtc/base/asyncsocket.h"
+#include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 
 namespace rtc {
@@ -220,7 +219,7 @@ FirewallManager::FirewallManager() {
 }
 
 FirewallManager::~FirewallManager() {
-  assert(servers_.empty());
+  RTC_DCHECK(servers_.empty());
 }
 
 void FirewallManager::AddServer(FirewallSocketServer* server) {
diff --git a/webrtc/base/flags.cc b/webrtc/base/flags.cc
index 248c5c3f18..a138b8fb9b 100644
--- a/webrtc/base/flags.cc
+++ b/webrtc/base/flags.cc
@@ -8,18 +8,19 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include "webrtc/base/flags.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include "webrtc/base/checks.h"
 
 #if defined(WEBRTC_WIN)
 #include "webrtc/base/win32.h"
 #include <shellapi.h>
 #endif
 
-#include "webrtc/base/flags.h"
-
 namespace rtc {
 // -----------------------------------------------------------------------------
 // Implementation of Flag
@@ -256,7 +257,8 @@ int FlagList::SetFlagsFromCommandLine(int* argc, const char** argv,
 }
 
 void FlagList::Register(Flag* flag) {
-  assert(flag != NULL && strlen(flag->name()) > 0);
+  RTC_DCHECK(flag);
+  RTC_DCHECK_GT(strlen(flag->name()), 0u);
   // NOTE: Don't call Lookup() within Register because it accesses the name_
   // of other flags in list_, and if the flags are coming from two different
   // compilation units, the initialization order between them is undefined, and
diff --git a/webrtc/base/flags.h b/webrtc/base/flags.h
index d16f12bad6..6ca50b5cea 100644
--- a/webrtc/base/flags.h
+++ b/webrtc/base/flags.h
@@ -23,8 +23,6 @@
 #ifndef WEBRTC_BASE_FLAGS_H__
 #define WEBRTC_BASE_FLAGS_H__
 
-#include <assert.h>
-
 #include "webrtc/base/checks.h"
 #include "webrtc/base/common.h"
 #include "webrtc/base/constructormagic.h"
@@ -88,43 +86,43 @@ class Flag {
 
   // Flag variables
   bool* bool_variable() const {
-    assert(type_ == BOOL);
+    RTC_DCHECK_EQ(BOOL, type_);
     return &variable_->b;
   }
 
   int* int_variable() const {
-    assert(type_ == INT);
+    RTC_DCHECK_EQ(INT, type_);
     return &variable_->i;
   }
 
   double* float_variable() const {
-    assert(type_ == FLOAT);
+    RTC_DCHECK_EQ(FLOAT, type_);
     return &variable_->f;
   }
 
   const char** string_variable() const {
-    assert(type_ == STRING);
+    RTC_DCHECK_EQ(STRING, type_);
     return &variable_->s;
   }
 
   // Default values
   bool bool_default() const {
-    assert(type_ == BOOL);
+    RTC_DCHECK_EQ(BOOL, type_);
     return default_.b;
   }
 
   int int_default() const {
-    assert(type_ == INT);
+    RTC_DCHECK_EQ(INT, type_);
     return default_.i;
   }
 
   double float_default() const {
-    assert(type_ == FLOAT);
+    RTC_DCHECK_EQ(FLOAT, type_);
     return default_.f;
   }
 
   const char* string_default() const {
-    assert(type_ == STRING);
+    RTC_DCHECK_EQ(STRING, type_);
     return default_.s;
   }
 
diff --git a/webrtc/base/maccocoasocketserver.mm b/webrtc/base/maccocoasocketserver.mm
index 123ffdc525..034737ebcc 100644
--- a/webrtc/base/maccocoasocketserver.mm
+++ b/webrtc/base/maccocoasocketserver.mm
@@ -11,7 +11,6 @@
 
 #import <Foundation/Foundation.h>
 #import <AppKit/AppKit.h>
-#include <assert.h>
 
 #include "webrtc/base/scoped_autorelease_pool.h"
 
diff --git a/webrtc/base/maccocoathreadhelper.mm b/webrtc/base/maccocoathreadhelper.mm
index 59ae6c4c99..70d920de39 100644
--- a/webrtc/base/maccocoathreadhelper.mm
+++ b/webrtc/base/maccocoathreadhelper.mm
@@ -9,11 +9,12 @@
  */
 // Helper function for using Cocoa with Posix threading.
 
-#import <assert.h>
 #import <Foundation/Foundation.h>
 
 #import "webrtc/base/maccocoathreadhelper.h"
 
+#include "webrtc/base/checks.h"
+
 namespace rtc {
 
 // Cocoa must be "put into multithreading mode" before Cocoa functionality can
@@ -34,7 +35,7 @@ void InitCocoaMultiThreading() {
     [hack drain];
   }
 
-  assert([NSThread isMultiThreaded]);
+  RTC_DCHECK([NSThread isMultiThreaded]);
 }
 
 }  // namespace rtc
diff --git a/webrtc/base/nattypes.cc b/webrtc/base/nattypes.cc
index 890a664095..1e37698f0d 100644
--- a/webrtc/base/nattypes.cc
+++ b/webrtc/base/nattypes.cc
@@ -8,10 +8,10 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include <assert.h>
-
 #include "webrtc/base/nattypes.h"
 
+#include "webrtc/base/checks.h"
+
 namespace rtc {
 
 class SymmetricNAT : public NAT {
@@ -44,11 +44,17 @@ public:
 
 NAT* NAT::Create(NATType type) {
   switch (type) {
-  case NAT_OPEN_CONE:       return new OpenConeNAT();
-  case NAT_ADDR_RESTRICTED: return new AddressRestrictedNAT();
-  case NAT_PORT_RESTRICTED: return new PortRestrictedNAT();
-  case NAT_SYMMETRIC:       return new SymmetricNAT();
-  default: assert(0);       return 0;
+    case NAT_OPEN_CONE:
+      return new OpenConeNAT();
+    case NAT_ADDR_RESTRICTED:
+      return new AddressRestrictedNAT();
+    case NAT_PORT_RESTRICTED:
+      return new PortRestrictedNAT();
+    case NAT_SYMMETRIC:
+      return new SymmetricNAT();
+    default:
+      RTC_NOTREACHED();
+      return 0;
   }
 }
 
diff --git a/webrtc/base/physicalsocketserver.cc b/webrtc/base/physicalsocketserver.cc
index c94b9a3ded..f0dc69fe67 100644
--- a/webrtc/base/physicalsocketserver.cc
+++ b/webrtc/base/physicalsocketserver.cc
@@ -13,8 +13,6 @@
 #pragma warning(disable:4786)
 #endif
 
-#include <assert.h>
-
 #ifdef MEMORY_SANITIZER
 #include <sanitizer/msan_interface.h>
 #endif
diff --git a/webrtc/base/sec_buffer.h b/webrtc/base/sec_buffer.h
index e6ffea4eb7..3ef720a9b2 100644
--- a/webrtc/base/sec_buffer.h
+++ b/webrtc/base/sec_buffer.h
@@ -73,16 +73,9 @@ class CSecBuffer: public CSecBufferBase {
     Clear();
   }
 
- private:
-  // A placeholder function for compile-time asserts on the class
-  void CompileAsserts() {
-    // never invoked...
-    assert(false); // _T("Notreached")
-
-    // This class must not extend the size of SecBuffer, since
-    // we use arrays of CSecBuffer in CSecBufferBundle below
-    cassert(sizeof(CSecBuffer<SSPIFree> == sizeof(SecBuffer)));
-  }
+  // This class must not extend the size of SecBuffer, since we use arrays of
+  // CSecBuffer in CSecBufferBundle below.
+  static_assert(sizeof(CSecBuffer<pfnFreeBuffer>) == sizeof(SecBuffer), "");
 };
 
 // Contains all generic implementation for the
diff --git a/webrtc/base/virtualsocketserver.h b/webrtc/base/virtualsocketserver.h
index 565222bfd2..cce0279d32 100644
--- a/webrtc/base/virtualsocketserver.h
+++ b/webrtc/base/virtualsocketserver.h
@@ -11,11 +11,10 @@
 #ifndef WEBRTC_BASE_VIRTUALSOCKETSERVER_H_
 #define WEBRTC_BASE_VIRTUALSOCKETSERVER_H_
 
-#include <assert.h>
-
 #include <deque>
 #include <map>
 
+#include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/messagequeue.h"
 #include "webrtc/base/socketserver.h"
@@ -86,7 +85,8 @@ class VirtualSocketServer : public SocketServer, public sigslot::has_slots<> {
   // is separate from calculations to drop based on queue size.
   double drop_probability() { return drop_prob_; }
   void set_drop_probability(double drop_prob) {
-    assert((0 <= drop_prob) && (drop_prob <= 1));
+    RTC_DCHECK_GE(drop_prob, 0.0);
+    RTC_DCHECK_LE(drop_prob, 1.0);
     drop_prob_ = drop_prob;
   }
 
diff --git a/webrtc/base/winping.cc b/webrtc/base/winping.cc
index be436c3cb0..1b0fa5d82f 100644
--- a/webrtc/base/winping.cc
+++ b/webrtc/base/winping.cc
@@ -10,12 +10,12 @@
 
 #include "webrtc/base/winping.h"
 
-#include <assert.h>
 #include <Iphlpapi.h>
 
 #include <algorithm>
 
 #include "webrtc/base/byteorder.h"
+#include "webrtc/base/checks.h"
 #include "webrtc/base/common.h"
 #include "webrtc/base/ipaddress.h"
 #include "webrtc/base/logging.h"
@@ -218,7 +218,7 @@ WinPing::PingResult WinPing::Ping(IPAddress ip,
     return PING_INVALID_PARAMS;
   }
 
-  assert(IsValid());
+  RTC_DCHECK(IsValid());
 
   IP_OPTION_INFORMATION ipopt;
   memset(&ipopt, 0, sizeof(ipopt));