diff --git a/mysql-test/suite/rpl/r/rpl_read_old_relay_log_info.result b/mysql-test/suite/rpl/r/rpl_read_old_relay_log_info.result
index 151a00a514b24..d4f7f3d982282 100644
--- a/mysql-test/suite/rpl/r/rpl_read_old_relay_log_info.result
+++ b/mysql-test/suite/rpl/r/rpl_read_old_relay_log_info.result
@@ -12,4 +12,11 @@ START SLAVE IO_THREAD;
 include/wait_for_slave_io_to_start.inc
 # Check that relay log coordinates are equal to those we saved in old-format_relay-log.info
 = , 0, slave-relay-bin.000001, 4
+#
+# MDEV-38020: Master & relay log info files read 2^31 and above incorrectly
+#
+connection server_2;
+include/stop_slave.inc
+include/rpl_restart_server.inc [server_number=2 parameters: --skip-slave-start]
+include/assert.inc [relay_log_pos should be 2147483648 after restart]
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_read_old_relay_log_info.test b/mysql-test/suite/rpl/t/rpl_read_old_relay_log_info.test
index d2206b5bef79a..db910d80c41a3 100644
--- a/mysql-test/suite/rpl/t/rpl_read_old_relay_log_info.test
+++ b/mysql-test/suite/rpl/t/rpl_read_old_relay_log_info.test
@@ -44,5 +44,30 @@ if (`SELECT "$master_file" != "" OR
   --die log coordinates changed
 }
 
+--echo #
+--echo # MDEV-38020: Master & relay log info files read 2^31 and above incorrectly
+--echo #
+
+--connection server_2
+--source include/stop_slave.inc
+
+# Create a relay-log.info file with a position value > 2^31
+--let $MYSQLD_DATADIR= `select @@datadir`
+--remove_file $MYSQLD_DATADIR/relay-log.info
+--write_file $MYSQLD_DATADIR/relay-log.info
+./slave-relay-bin.000001
+2147483648
+
+0
+EOF
+
+--let $rpl_server_number= 2
+--let $rpl_server_parameters= --skip-slave-start
+--source include/rpl_restart_server.inc
+
+--let $assert_text= relay_log_pos should be 2147483648 after restart
+--let $assert_cond= [SHOW SLAVE STATUS, Relay_Log_Pos, 1] = 2147483648
+--source include/assert.inc
+
 --let $rpl_only_running_threads= 1
 --source include/rpl_end.inc
diff --git a/sql/rpl_mi.cc b/sql/rpl_mi.cc
index b19a585f47ebf..bb77c46d57f57 100644
--- a/sql/rpl_mi.cc
+++ b/sql/rpl_mi.cc
@@ -448,7 +448,8 @@ file '%s')", fname);
     }
 
     mi->fd = fd;
-    int port, connect_retry, master_log_pos, lines;
+    int port, connect_retry, lines;
+    ulonglong master_log_pos;
     int ssl= 0, ssl_verify_server_cert= 0;
     float master_heartbeat_period= 0.0;
     char *first_non_digit;
@@ -496,7 +497,7 @@ file '%s')", fname);
     else
       lines= 7;
 
-    if (init_intvar_from_file(&master_log_pos, &mi->file, 4) ||
+    if (init_ulonglongvar_from_file(&master_log_pos, &mi->file, 4) ||
         init_strvar_from_file(mi->host, sizeof(mi->host), &mi->file, 0) ||
         init_strvar_from_file(mi->user, sizeof(mi->user), &mi->file, "test") ||
         init_strvar_from_file(mi->password, sizeof(mi->password),
diff --git a/sql/rpl_rli.cc b/sql/rpl_rli.cc
index 320937ed82900..4ed2f55e8317c 100644
--- a/sql/rpl_rli.cc
+++ b/sql/rpl_rli.cc
@@ -321,7 +321,8 @@ Failed to open the existing relay log info file '%s' (errno %d)",
       }
     }
 
-    int relay_log_pos, master_log_pos, lines;
+    ulonglong relay_log_pos, master_log_pos;
+    int lines;
     char *first_non_digit;
 
     /*
@@ -374,12 +375,12 @@ Failed to open the existing relay log info file '%s' (errno %d)",
     else
       DBUG_PRINT("info", ("relay_log_info file is in old format."));
 
-    if (init_intvar_from_file(&relay_log_pos,
+    if (init_ulonglongvar_from_file(&relay_log_pos,
                               &info_file, BIN_LOG_HEADER_SIZE) ||
         init_strvar_from_file(group_master_log_name,
                               sizeof(group_master_log_name),
                               &info_file, "") ||
-        init_intvar_from_file(&master_log_pos, &info_file, 0) ||
+        init_ulonglongvar_from_file(&master_log_pos, &info_file, 0) ||
         (lines >= LINES_IN_RELAY_LOG_INFO_WITH_DELAY &&
          init_intvar_from_file(&sql_delay, &info_file, 0)))
     {
diff --git a/sql/slave.cc b/sql/slave.cc
index 15eeae3145542..6e0b86fc968ac 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -1608,6 +1608,27 @@ int init_intvar_from_file(int* var, IO_CACHE* f, int default_val)
   DBUG_RETURN(1);
 }
 
+int init_ulonglongvar_from_file(ulonglong* var, IO_CACHE* f,
+                                ulonglong default_val)
+{
+  char buf[MY_INT64_NUM_DECIMAL_DIGITS];
+  int error;
+  DBUG_ENTER("init_ulonglongvar_from_file");
+
+
+  if (my_b_gets(f, buf, sizeof(buf)))
+  {
+    *var = (ulonglong) my_strtoll10(buf, (char**) 0, &error);
+    DBUG_RETURN(0);
+  }
+  else if (default_val)
+  {
+    *var = default_val;
+    DBUG_RETURN(0);
+  }
+  DBUG_RETURN(1);
+}
+
 int init_floatvar_from_file(float* var, IO_CACHE* f, float default_val)
 {
   char buf[16];
diff --git a/sql/slave.h b/sql/slave.h
index 02de9135c2a10..ce25bebf730ba 100644
--- a/sql/slave.h
+++ b/sql/slave.h
@@ -266,6 +266,8 @@ int apply_event_and_update_pos_for_parallel(Log_event* ev, THD* thd,
                                             struct rpl_group_info *rgi);
 
 int init_intvar_from_file(int* var, IO_CACHE* f, int default_val);
+int init_ulonglongvar_from_file(ulonglong* var, IO_CACHE* f,
+                                ulonglong default_val);
 int init_floatvar_from_file(float* var, IO_CACHE* f, float default_val);
 int init_strvar_from_file(char *var, int max_size, IO_CACHE *f,
                           const char *default_val);