diff --git a/proxy/http/HttpSM.cc b/proxy/http/HttpSM.cc
index da74312a0e5..e7b716020cb 100644
--- a/proxy/http/HttpSM.cc
+++ b/proxy/http/HttpSM.cc
@@ -2352,7 +2352,7 @@ HttpSM::add_to_existing_request()
       // bytes are received back
       this->t_state.set_connect_fail(EIO);
       ip_iter->second->connect_sms.insert(this);
-      Debug("http_connect", "Add entry to connection queue. size=%" PRId64, ip_iter->second->connect_sms.size());
+      Debug("http_connect", "Add entry to connection queue. size=%zd", ip_iter->second->connect_sms.size());
       retval = true;
       break;
     }
diff --git a/proxy/http/HttpTunnel.cc b/proxy/http/HttpTunnel.cc
index 9d6a6b32fd7..c8574ab5483 100644
--- a/proxy/http/HttpTunnel.cc
+++ b/proxy/http/HttpTunnel.cc
@@ -986,7 +986,7 @@ HttpTunnel::producer_run(HttpTunnelProducer *p)
           p->handler_state = HTTP_SM_POST_SUCCESS;
         }
       }
-      Debug("http_tunnel", "Start write vio %ld bytes", c_write);
+      Debug("http_tunnel", "Start write vio %" PRId64 " bytes", c_write);
       // Start the writes now that we know we will consume all the initial data
       c->write_vio = c->vc->do_io_write(this, c_write, c->buffer_reader);
       ink_assert(c_write > 0);
@@ -1013,7 +1013,7 @@ HttpTunnel::producer_run(HttpTunnelProducer *p)
       if (read_start_pos > 0) {
         p->read_vio = ((CacheVC *)p->vc)->do_io_pread(this, producer_n, p->read_buffer, read_start_pos);
       } else {
-        Debug("http_tunnel", "Start read vio %ld bytes", producer_n);
+        Debug("http_tunnel", "Start read vio %" PRId64 " bytes", producer_n);
         p->read_vio = p->vc->do_io_read(this, producer_n, p->read_buffer);
         p->read_vio->reenable();
       }
diff --git a/proxy/http2/Http2Stream.cc b/proxy/http2/Http2Stream.cc
index e9c66d46764..54ac07c50ce 100644
--- a/proxy/http2/Http2Stream.cc
+++ b/proxy/http2/Http2Stream.cc
@@ -549,7 +549,7 @@ Http2Stream::initiating_close()
   if (!closed) {
     SCOPED_MUTEX_LOCK(lock, this->mutex, this_ethread());
     REMEMBER(NO_EVENT, this->reentrancy_count);
-    Http2StreamDebug("initiating_close client_window=%" PRId64 " session_window=%" PRId64, _peer_rwnd,
+    Http2StreamDebug("initiating_close client_window=%zd session_window=%zd", _peer_rwnd,
                      this->get_connection_state().get_peer_rwnd());
 
     if (this->is_state_writeable()) { // Let the other end know we are going away
@@ -731,8 +731,8 @@ Http2Stream::update_write_request(bool call_update)
   IOBufferReader *vio_reader = write_vio.get_reader();
 
   if (write_vio.ntodo() > 0 && (!vio_reader->is_read_avail_more_than(0))) {
-    Http2StreamDebug("update_write_request give up without doing anything ntodo=%" PRId64 " is_read_avail=%d client_window=%" PRId64
-                     " session_window=%" PRId64,
+    Http2StreamDebug("update_write_request give up without doing anything ntodo=%" PRId64 " is_read_avail=%d client_window=%zd"
+                     " session_window=%zd",
                      write_vio.ntodo(), vio_reader->is_read_avail_more_than(0), _peer_rwnd,
                      this->get_connection_state().get_peer_rwnd());
     return;