diff --git a/backup.c b/backup.c
index 9b6db171..9e3bd0c0 100644
--- a/backup.c
+++ b/backup.c
@@ -103,7 +103,7 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 			pgBackup   *prev_backup;
 
 			/* find last completed database backup */
-			prev_backup = catalog_get_last_full_backup(backup_list);
+			prev_backup = catalog_get_last_data_backup(backup_list);
 			if (prev_backup == NULL)
 			{
 				if (current.full_backup_on_error)
@@ -185,6 +185,10 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 	/*
 	 * To take incremental backup, the file list of the latest validated
 	 * full database backup is needed.
+	 * TODO: fix for issue #154
+	 * When a backup list is deleted with rm command or pg_rman's delete command with '--force' option,
+	 * pg_rman can't detect there is a missing piece of backup.
+	 * We need the way tracing the backup chains or something else...
 	 */
 	if (current.backup_mode < BACKUP_MODE_FULL)
 	{
@@ -192,7 +196,7 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 		uint32		xlogid, xrecoff;
 
 		/* find last completed database backup */
-		prev_backup = catalog_get_last_full_backup(backup_list);
+		prev_backup = catalog_get_last_data_backup(backup_list);
 		if (prev_backup == NULL || prev_backup->tli != current.tli)
 		{
 			if (current.full_backup_on_error)
diff --git a/catalog.c b/catalog.c
index 2648b094..80749c6e 100644
--- a/catalog.c
+++ b/catalog.c
@@ -266,7 +266,7 @@ catalog_get_backup_list(const pgBackupRange *range)
  * Find the last completed database full valid backup from the backup list.
  */
 pgBackup *
-catalog_get_last_full_backup(parray *backup_list)
+catalog_get_last_data_backup(parray *backup_list)
 {
 	int			i;
 	pgBackup   *backup = NULL;
@@ -276,9 +276,8 @@ catalog_get_last_full_backup(parray *backup_list)
 	{
 		backup = (pgBackup *) parray_get(backup_list, i);
 
-		/* Return the first full valid backup. */
-		if (backup->backup_mode == BACKUP_MODE_FULL &&
-			backup->status == BACKUP_STATUS_OK)
+		/* we need completed database backup */
+		if (backup -> status == BACKUP_STATUS_OK && HAVE_DATABASE(backup))
 			return backup;
 	}
 
diff --git a/expected/backup.out b/expected/backup.out
index 1734572a..67c9692d 100644
--- a/expected/backup.out
+++ b/expected/backup.out
@@ -16,15 +16,23 @@
 0
 1
 ###### BACKUP COMMAND TEST-0005 ######
+###### Make sure that pg_rman does not take a differential backup, but a incremental backup ######
+0
+CREATE TABLE
+INSERT 0 1000000
+0
+0
+INCR 16kB OK
+###### BACKUP COMMAND TEST-0006 ######
 ###### full backup with compression ######
 0
 1
 1
-###### BACKUP COMMAND TEST-0006 ######
+###### BACKUP COMMAND TEST-0007 ######
 ###### full backup with smooth checkpoint ######
 0
 1
-###### BACKUP COMMAND TEST-0007 ######
+###### BACKUP COMMAND TEST-0008 ######
 ###### switch backup mode from incremental to full ######
 incremental backup without validated full backup
 INFO: copying database files
@@ -43,7 +51,7 @@ INFO: Please execute 'pg_rman validate' to verify the files are correctly copied
 0
 1
 1
-###### BACKUP COMMAND TEST-0008 ######
+###### BACKUP COMMAND TEST-0009 ######
 ###### switch backup mode from archive to full ######
 archive backup without validated full backup
 ERROR: cannot take an incremental backup
@@ -61,7 +69,7 @@ INFO: Please execute 'pg_rman validate' to verify the files are correctly copied
 0
 1
 1
-###### BACKUP COMMAND TEST-0009 ######
+###### BACKUP COMMAND TEST-0010 ######
 ###### failure in backup with different system identifier database ######
 ERROR: could not start backup
 DETAIL: system identifier of target database is different from the one of initially configured database
diff --git a/pg_rman.h b/pg_rman.h
index 1394f634..63e1e46e 100644
--- a/pg_rman.h
+++ b/pg_rman.h
@@ -285,7 +285,7 @@ extern void pgBackupValidate(pgBackup *backup, bool size_only, bool for_get_time
 /* in catalog.c */
 extern pgBackup *catalog_get_backup(time_t timestamp);
 extern parray *catalog_get_backup_list(const pgBackupRange *range);
-extern pgBackup *catalog_get_last_full_backup(parray *backup_list);
+extern pgBackup *catalog_get_last_data_backup(parray *backup_list);
 extern pgBackup *catalog_get_last_arclog_backup(parray *backup_list);
 extern pgBackup *catalog_get_last_srvlog_backup(parray *backup_list);
 
diff --git a/sql/backup.sh b/sql/backup.sh
index 0eeb62d0..85430ce7 100644
--- a/sql/backup.sh
+++ b/sql/backup.sh
@@ -118,7 +118,6 @@ pg_rman validate -B ${BACKUP_PATH} --quiet
 pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0001.log 2>&1
 grep -c OK ${TEST_BASE}/TEST-0001.log
 
-
 echo '###### BACKUP COMMAND TEST-0002 ######'
 echo '###### incremental backup mode ######'
 pg_rman backup -B ${BACKUP_PATH} -b incremental -p ${TEST_PGPORT} -d postgres --quiet;echo $?
@@ -141,7 +140,23 @@ pg_rman validate -B ${BACKUP_PATH} --quiet
 pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0004.log 2>&1
 grep -c OK ${TEST_BASE}/TEST-0004.log
 
+# If a differential backup was taken, the size of third backup is same as the second one and the size is bigger (XXMB).
+# 16kB is the base backup size if nothing was changed in the database cluster.
 echo '###### BACKUP COMMAND TEST-0005 ######'
+echo '###### Make sure that pg_rman does not take a differential backup, but a incremental backup ######'
+init_catalog
+pg_rman backup -B ${BACKUP_PATH} -b full -p ${TEST_PGPORT} -d postgres --quiet;echo $?
+pg_rman validate -B ${BACKUP_PATH} --quiet
+psql -p ${TEST_PGPORT} -d postgres -c 'create table test (c1 int);'
+psql -p ${TEST_PGPORT} -d postgres -c 'insert into test values(generate_series(1,1000000));' 
+pg_rman backup -B ${BACKUP_PATH} -b incremental -p ${TEST_PGPORT} -d postgres --quiet;echo $?
+pg_rman validate -B ${BACKUP_PATH} --quiet
+pg_rman backup -B ${BACKUP_PATH} -b incremental -p ${TEST_PGPORT} -d postgres --quiet;echo $?
+pg_rman validate -B ${BACKUP_PATH} --quiet
+pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0012.log 2>&1
+cat ${TEST_BASE}/TEST-0012.log  | head -n 4 | tail -n 1 | awk '{print $5, $6, $13}' 
+
+echo '###### BACKUP COMMAND TEST-0006 ######'
 echo '###### full backup with compression ######'
 init_catalog
 pg_rman backup -B ${BACKUP_PATH} -b full -s -Z -p ${TEST_PGPORT} -d postgres --quiet;echo $?
@@ -150,7 +165,7 @@ pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0005.log 2>&1
 grep -c OK ${TEST_BASE}/TEST-0005.log
 grep OK ${TEST_BASE}/TEST-0005.log | grep -c true
 
-echo '###### BACKUP COMMAND TEST-0006 ######'
+echo '###### BACKUP COMMAND TEST-0007 ######'
 echo '###### full backup with smooth checkpoint ######'
 init_catalog
 pg_rman backup -B ${BACKUP_PATH} -b full -s -C -p ${TEST_PGPORT} -d postgres --quiet;echo $?
@@ -158,7 +173,7 @@ pg_rman validate -B ${BACKUP_PATH} --quiet
 pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0006.log 2>&1
 grep -c OK ${TEST_BASE}/TEST-0006.log
 
-echo '###### BACKUP COMMAND TEST-0007 ######'
+echo '###### BACKUP COMMAND TEST-0008 ######'
 echo '###### switch backup mode from incremental to full ######'
 init_catalog
 echo 'incremental backup without validated full backup'
@@ -171,7 +186,7 @@ pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0010.log 2>&1
 grep OK ${TEST_BASE}/TEST-0010.log | grep FULL | wc -l
 grep ERROR ${TEST_BASE}/TEST-0010.log | grep INCR | wc -l
 
-echo '###### BACKUP COMMAND TEST-0008 ######'
+echo '###### BACKUP COMMAND TEST-0009 ######'
 echo '###### switch backup mode from archive to full ######'
 init_catalog
 echo 'archive backup without validated full backup'
@@ -184,7 +199,7 @@ pg_rman show detail -B ${BACKUP_PATH} > ${TEST_BASE}/TEST-0011.log 2>&1
 grep OK ${TEST_BASE}/TEST-0011.log | grep FULL | wc -l
 grep ERROR ${TEST_BASE}/TEST-0011.log | grep ARCH | wc -l
 
-echo '###### BACKUP COMMAND TEST-0009 ######'
+echo '###### BACKUP COMMAND TEST-0010 ######'
 echo '###### failure in backup with different system identifier database ######'
 init_catalog
 pg_ctl stop -m immediate > /dev/null 2>&1