diff --git a/compiler/cpp/src/generate/t_cpp_generator.cc b/compiler/cpp/src/generate/t_cpp_generator.cc
index d6ebc32db..8dfb0ee3d 100644
--- a/compiler/cpp/src/generate/t_cpp_generator.cc
+++ b/compiler/cpp/src/generate/t_cpp_generator.cc
@@ -1917,8 +1917,8 @@ void t_cpp_generator::generate_service_multiface(t_service* tservice) {
       indent() << function_signature(*f_iter, "") << " {" << endl;
     indent_up();
     f_header_ <<
-      indent() << "uint32_t sz = ifaces_.size();" << endl <<
-      indent() << "for (uint32_t i = 0; i < sz; ++i) {" << endl;
+      indent() << "size_t sz = ifaces_.size();" << endl <<
+      indent() << "for (size_t i = 0; i < sz; ++i) {" << endl;
     if (!(*f_iter)->get_returntype()->is_void()) {
       f_header_ <<
         indent() << "  if (i == sz - 1) {" << endl;
@@ -3622,17 +3622,17 @@ void t_cpp_generator::generate_serialize_container(ofstream& out,
       "xfer += oprot->writeMapBegin(" <<
       type_to_enum(((t_map*)ttype)->get_key_type()) << ", " <<
       type_to_enum(((t_map*)ttype)->get_val_type()) << ", " <<
-      prefix << ".size());" << endl;
+      "static_cast<uint32_t>(" << prefix << ".size()));" << endl;
   } else if (ttype->is_set()) {
     indent(out) <<
       "xfer += oprot->writeSetBegin(" <<
       type_to_enum(((t_set*)ttype)->get_elem_type()) << ", " <<
-      prefix << ".size());" << endl;
+      "static_cast<uint32_t>(" << prefix << ".size()));" << endl;
   } else if (ttype->is_list()) {
     indent(out) <<
       "xfer += oprot->writeListBegin(" <<
       type_to_enum(((t_list*)ttype)->get_elem_type()) << ", " <<
-      prefix << ".size());" << endl;
+      "static_cast<uint32_t>(" << prefix << ".size()));" << endl;
   }
 
   string iter = tmp("_iter");
diff --git a/lib/cpp/src/transport/TBufferTransports.h b/lib/cpp/src/transport/TBufferTransports.h
index f6d52d598..92492d7e1 100644
--- a/lib/cpp/src/transport/TBufferTransports.h
+++ b/lib/cpp/src/transport/TBufferTransports.h
@@ -108,7 +108,7 @@ class TBufferBase : public TVirtualTransport<TBufferBase> {
     if (TDB_LIKELY(static_cast<ptrdiff_t>(*len) <= rBound_ - rBase_)) {
       // With strict aliasing, writing to len shouldn't force us to
       // refetch rBase_ from memory.  TODO(dreiss): Verify this.
-      *len = rBound_ - rBase_;
+      *len = static_cast<uint32_t>(rBound_ - rBase_);
       return rBase_;
     }
     return borrowSlow(buf, len);
@@ -568,7 +568,7 @@ class TMemoryBuffer : public TVirtualTransport<TMemoryBuffer, TBufferBase> {
   // TODO(dreiss): Make bufPtr const.
   void getBuffer(uint8_t** bufPtr, uint32_t* sz) {
     *bufPtr = rBase_;
-    *sz = wBase_ - rBase_;
+    *sz = static_cast<uint32_t>(wBase_ - rBase_);
   }
 
   std::string getBufferAsString() {
@@ -656,11 +656,11 @@ class TMemoryBuffer : public TVirtualTransport<TMemoryBuffer, TBufferBase> {
 
   uint32_t available_read() const {
     // Remember, wBase_ is the real rBound_.
-    return wBase_ - rBase_;
+    return static_cast<uint32_t>(wBase_ - rBase_);
   }
 
   uint32_t available_write() const {
-    return wBound_ - wBase_;
+    return static_cast<uint32_t>(wBound_ - wBase_);
   }
 
   // Returns a pointer to where the client can write data to append to