diff --git a/libs/libc/stream/lib_syslograwstream.c b/libs/libc/stream/lib_syslograwstream.c
index 68a23da340644..de99b9b9a3815 100644
--- a/libs/libc/stream/lib_syslograwstream.c
+++ b/libs/libc/stream/lib_syslograwstream.c
@@ -260,6 +260,7 @@ void lib_syslograwstream_open(FAR struct lib_syslograwstream_s *stream)
   stream->common.putc  = syslograwstream_putc;
   stream->common.puts  = syslograwstream_puts;
   stream->common.nput  = 0;
+  stream->last_ch      = '\0';
 
 #ifdef CONFIG_SYSLOG_BUFFER
   stream->common.flush = syslograwstream_flush;