diff --git a/bin/expected/reorg.out b/bin/expected/reorg.out
index 8793c48..86d7a0e 100755
--- a/bin/expected/reorg.out
+++ b/bin/expected/reorg.out
@@ -46,6 +46,10 @@ CREATE TABLE tbl_with_dropped_toast (
 	PRIMARY KEY (i, j)
 );
 ALTER TABLE tbl_with_dropped_toast CLUSTER ON tbl_with_dropped_toast_pkey;
+CREATE TABLE tbl_badindex (
+	id integer PRIMARY KEY,
+	n integer
+);
 --
 -- insert data
 --
@@ -71,6 +75,11 @@ CREATE VIEW view_for_dropped_column AS
 INSERT INTO tbl_with_dropped_toast VALUES(1, 10, 'abc');
 INSERT INTO tbl_with_dropped_toast VALUES(2, 20, sqrt(2::numeric(1000,999))::text || sqrt(3::numeric(1000,999))::text);
 ALTER TABLE tbl_with_dropped_toast DROP COLUMN t;
+INSERT INTO tbl_badindex VALUES(1, 10);
+INSERT INTO tbl_badindex VALUES(2, 10);
+CREATE UNIQUE INDEX CONCURRENTLY idx_badindex_n ON tbl_badindex (n);
+ERROR:  could not create unique index "idx_badindex_n"
+DETAIL:  Key (n)=(10) is duplicated.
 --
 -- before
 --
@@ -99,6 +108,7 @@ SELECT * FROM tbl_with_dropped_toast;
 -- do reorg
 --
 \! pg_reorg --dbname=contrib_regression --no-order
+WARNING: skipping invalid index: CREATE UNIQUE INDEX idx_badindex_n ON tbl_badindex USING btree (n)
 \! pg_reorg --dbname=contrib_regression
 \! pg_reorg --dbname=contrib_regression --table=tbl_cluster
 --
diff --git a/bin/pg_reorg.c b/bin/pg_reorg.c
index 4875976..2939f4c 100755
--- a/bin/pg_reorg.c
+++ b/bin/pg_reorg.c
@@ -460,7 +460,9 @@ reorg_one_table(const reorg_table *table, const char *orderby)
 
 	params[0] = utoa(table->target_oid, buffer);
 	res = execute("SELECT indexrelid,"
-		" reorg.reorg_indexdef(indexrelid, indrelid)"
+		" reorg.reorg_indexdef(indexrelid, indrelid),"
+		" indisvalid,"
+		" pg_get_indexdef(indexrelid)"
 		" FROM pg_index WHERE indrelid = $1", 1, params);
 
 	num = PQntuples(res);
@@ -468,9 +470,18 @@ reorg_one_table(const reorg_table *table, const char *orderby)
 	{
 		reorg_index	index;
 		int			c = 0;
+		const char *isvalid;
+		const char *indexdef;
 
 		index.target_oid = getoid(res, i, c++);
 		index.create_index = getstr(res, i, c++);
+		isvalid = getstr(res, i, c++);
+		indexdef = getstr(res, i, c++);
+
+		if (isvalid && isvalid[0] == 'f') {
+			elog(WARNING, "skipping invalid index: %s", indexdef);
+			continue;
+		}
 
 		elog(DEBUG2, "[%d]", i);
 		elog(DEBUG2, "target_oid   : %u", index.target_oid);
diff --git a/bin/sql/reorg.sql b/bin/sql/reorg.sql
index 1760c98..863d2ce 100755
--- a/bin/sql/reorg.sql
+++ b/bin/sql/reorg.sql
@@ -55,6 +55,11 @@ CREATE TABLE tbl_with_dropped_toast (
 );
 ALTER TABLE tbl_with_dropped_toast CLUSTER ON tbl_with_dropped_toast_pkey;
 
+CREATE TABLE tbl_badindex (
+	id integer PRIMARY KEY,
+	n integer
+);
+
 --
 -- insert data
 --
@@ -86,6 +91,11 @@ CREATE VIEW view_for_dropped_column AS
 INSERT INTO tbl_with_dropped_toast VALUES(1, 10, 'abc');
 INSERT INTO tbl_with_dropped_toast VALUES(2, 20, sqrt(2::numeric(1000,999))::text || sqrt(3::numeric(1000,999))::text);
 ALTER TABLE tbl_with_dropped_toast DROP COLUMN t;
+
+INSERT INTO tbl_badindex VALUES(1, 10);
+INSERT INTO tbl_badindex VALUES(2, 10);
+CREATE UNIQUE INDEX CONCURRENTLY idx_badindex_n ON tbl_badindex (n);
+
 --
 -- before
 --
diff --git a/lib/reorg.c b/lib/reorg.c
index 3986f0b..22aa5c7 100755
--- a/lib/reorg.c
+++ b/lib/reorg.c
@@ -705,6 +705,7 @@ reorg_swap(PG_FUNCTION_ARGS)
 		"       pg_catalog.pg_class Y"
 		" WHERE I.indrelid = $1"
 		"   AND I.indexrelid = X.oid"
+		"   AND I.indisvalid"
 		"   AND Y.oid = ('reorg.index_' || X.oid)::regclass",
 		1, argtypes, values, nulls);