diff --git a/FuzzerCorpus.h b/FuzzerCorpus.h
index 48b5a2c..12a75fe 100644
--- a/FuzzerCorpus.h
+++ b/FuzzerCorpus.h
@@ -336,7 +336,8 @@
   void PrintFeatureSet() {
     for (size_t i = 0; i < kFeatureSetSize; i++) {
       if(size_t Sz = GetFeature(i))
-        Printf("[%zd: id %zd sz%zd] ", i, SmallestElementPerFeature[i], Sz);
+        Printf("[%zd: id %zd sz%zd] ", i, (size_t)SmallestElementPerFeature[i],
+               Sz);
     }
     Printf("\n\t");
     for (size_t i = 0; i < Inputs.size(); i++)
diff --git a/FuzzerDriver.cpp b/FuzzerDriver.cpp
index af9c260..6b25aa9 100644
--- a/FuzzerDriver.cpp
+++ b/FuzzerDriver.cpp
@@ -163,13 +163,13 @@
         auto Val = MyStol(Str);
         *FlagDescriptions[F].IntFlag = static_cast<int>(Val);
         if (Flags.verbosity >= 2)
-          Printf("Flag: %s %d\n", Name, Val);
+          Printf("Flag: %s %d\n", Name, (int)Val);
         return true;
       } else if (FlagDescriptions[F].UIntFlag) {
         auto Val = std::stoul(Str);
         *FlagDescriptions[F].UIntFlag = static_cast<unsigned int>(Val);
         if (Flags.verbosity >= 2)
-          Printf("Flag: %s %u\n", Name, Val);
+          Printf("Flag: %s %u\n", Name, (uint32_t)Val);
         return true;
       } else if (FlagDescriptions[F].StrFlag) {
         *FlagDescriptions[F].StrFlag = Str;
diff --git a/FuzzerLoop.cpp b/FuzzerLoop.cpp
index 6f415dd..75c2fb7 100644
--- a/FuzzerLoop.cpp
+++ b/FuzzerLoop.cpp
@@ -125,8 +125,8 @@
 void Fuzzer::HandleMalloc(size_t Size) {
   if (!Options.MallocLimitMb || (Size >> 20) < (size_t)Options.MallocLimitMb)
     return;
-  Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n", GetPid(),
-         Size);
+  Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n",
+         (int)GetPid(), Size);
   Printf("   To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
   PrintStackTrace();
   DumpCurrentUnit("oom-");
@@ -568,7 +568,7 @@
 
 void Fuzzer::CrashOnOverwrittenData() {
   Printf("==%d== ERROR: libFuzzer: fuzz target overwrites its const input\n",
-         GetPid());
+         (int)GetPid());
   PrintStackTrace();
   Printf("SUMMARY: libFuzzer: overwrites-const-input\n");
   DumpCurrentUnit("crash-");