diff --git a/CHANGELOG.md b/CHANGELOG.md
index a4fdaf92..35b24b5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ Technically, two changes are breaking changes, but in practice these are extreme
 * Conn.Begin and Conn.BeginTx return a Tx interface instead of the internal dbTx struct. This is necessary for the Conn.Begin method to signature as other methods that begin a transaction.
 * Add Conn() to Tx interface. This is necessary to allow code using a Tx to access the *Conn (and pgconn.PgConn) on which the Tx is executing.
 
+## Fixes
+
+* Releasing a busy connection closes the connection instead of returning an unusable connection to the pool
+
 # 4.0.1 (September 19, 2019)
 
 * Fix statement cache cleanup.
diff --git a/go.mod b/go.mod
index 6e012e54..7d93e082 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,7 @@ go 1.12
 require (
 	github.com/cockroachdb/apd v1.1.0
 	github.com/gofrs/uuid v3.2.0+incompatible
-	github.com/jackc/pgconn v1.0.1
+	github.com/jackc/pgconn v1.1.0
 	github.com/jackc/pgio v1.0.0
 	github.com/jackc/pgproto3/v2 v2.0.0
 	github.com/jackc/pgtype v1.0.1
diff --git a/go.sum b/go.sum
index ff0e5499..0f20b219 100644
--- a/go.sum
+++ b/go.sum
@@ -28,6 +28,8 @@ github.com/jackc/pgconn v1.0.0 h1:HFtb+O3S+OgYs56mcFuFHiUStvABkdUrS+UrPgKqfMs=
 github.com/jackc/pgconn v1.0.0/go.mod h1:GgY/Lbj1VonNaVdNUHs9AwWom3yP2eymFQ1C8z9r/Lk=
 github.com/jackc/pgconn v1.0.1 h1:ZANo4pIkeHKIVD1cQMcxu8fwrwIICLblzi9HCjooZeQ=
 github.com/jackc/pgconn v1.0.1/go.mod h1:GgY/Lbj1VonNaVdNUHs9AwWom3yP2eymFQ1C8z9r/Lk=
+github.com/jackc/pgconn v1.1.0 h1:10i6DMVJOSko/sD3FLpFKBHONzDGKkX8pbLyHC8B92o=
+github.com/jackc/pgconn v1.1.0/go.mod h1:GgY/Lbj1VonNaVdNUHs9AwWom3yP2eymFQ1C8z9r/Lk=
 github.com/jackc/pgio v1.0.0 h1:g12B9UwVnzGhueNavwioyEEpAmqMe1E/BN9ES+8ovkE=
 github.com/jackc/pgio v1.0.0/go.mod h1:oP+2QK2wFfUWgr+gxjoBH9KGBb31Eio69xUb0w5bYf8=
 github.com/jackc/pgmock v0.0.0-20190831213851-13a1b77aafa2/go.mod h1:fGZlG77KXmcq05nJLRkk0+p82V8B8Dw8KN2/V9c/OAE=
diff --git a/pgxpool/conn.go b/pgxpool/conn.go
index 315eb09d..1172fbcb 100644
--- a/pgxpool/conn.go
+++ b/pgxpool/conn.go
@@ -27,7 +27,7 @@ func (c *Conn) Release() {
 	c.res = nil
 
 	now := time.Now()
-	if conn.IsClosed() || conn.PgConn().TxStatus() != 'I' || (now.Sub(res.CreationTime()) > c.p.maxConnLifetime) {
+	if conn.IsClosed() || conn.PgConn().IsBusy() || conn.PgConn().TxStatus() != 'I' || (now.Sub(res.CreationTime()) > c.p.maxConnLifetime) {
 		res.Destroy()
 		return
 	}
diff --git a/pgxpool/pool_test.go b/pgxpool/pool_test.go
index d6640a71..8db8f169 100644
--- a/pgxpool/pool_test.go
+++ b/pgxpool/pool_test.go
@@ -210,6 +210,26 @@ func TestConnReleaseChecksMaxConnLifetime(t *testing.T) {
 	assert.EqualValues(t, 0, stats.TotalConns())
 }
 
+func TestConnReleaseClosesBusyConn(t *testing.T) {
+	t.Parallel()
+
+	db, err := pgxpool.Connect(context.Background(), os.Getenv("PGX_TEST_DATABASE"))
+	require.NoError(t, err)
+	defer db.Close()
+
+	c, err := db.Acquire(context.Background())
+	require.NoError(t, err)
+
+	_, err = c.Query(context.Background(), "select generate_series(1,10)")
+	require.NoError(t, err)
+
+	c.Release()
+	waitForReleaseToComplete()
+
+	stats := db.Stat()
+	assert.EqualValues(t, 0, stats.TotalConns())
+}
+
 func TestPoolBackgroundChecksMaxConnLifetime(t *testing.T) {
 	t.Parallel()