diff --git a/connection.go b/connection.go
index 2ff3cc57..e30ce681 100644
--- a/connection.go
+++ b/connection.go
@@ -37,6 +37,15 @@ func (e NotSingleRowError) Error() string {
 	return fmt.Sprintf("Expected to find 1 row exactly, instead found %d", e.RowCount)
 }
 
+type UnexpectedColumnCountError struct {
+	ExpectedCount int16
+	ActualCount   int16
+}
+
+func (e UnexpectedColumnCountError) Error() string {
+	return fmt.Sprintf("Expected result to have %d column(s), instead it has %d", e.ExpectedCount, e.ActualCount)
+}
+
 func Connect(parameters ConnectionParameters) (c *Connection, err error) {
 	c = new(Connection)
 
@@ -165,11 +174,16 @@ func (c *Connection) SelectRow(sql string) (row map[string]interface{}, err erro
 	return
 }
 
+// Returns a UnexpectedColumnCountError if exactly one column is not found
 // Returns a NotSingleRowError if exactly one row is not found
 func (c *Connection) SelectValue(sql string) (v interface{}, err error) {
 	var numRowsFound int64
 
 	onDataRow := func(r *DataRowReader) error {
+		if len(r.fields) != 1 {
+			return UnexpectedColumnCountError{ExpectedCount: 1, ActualCount: int16(len(r.fields))}
+		}
+
 		numRowsFound++
 		v = r.ReadValue()
 		return nil
@@ -183,9 +197,14 @@ func (c *Connection) SelectValue(sql string) (v interface{}, err error) {
 	return
 }
 
+// Returns a UnexpectedColumnCountError if exactly one column is not found
 func (c *Connection) SelectValues(sql string) (values []interface{}, err error) {
 	values = make([]interface{}, 0, 8)
 	onDataRow := func(r *DataRowReader) error {
+		if len(r.fields) != 1 {
+			return UnexpectedColumnCountError{ExpectedCount: 1, ActualCount: int16(len(r.fields))}
+		}
+
 		values = append(values, r.ReadValue())
 		return nil
 	}
diff --git a/connection_test.go b/connection_test.go
index 70fae107..efb3952f 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -236,6 +236,11 @@ func TestConnectionSelectValue(t *testing.T) {
 	if _, ok := err.(NotSingleRowError); !ok {
 		t.Error("Multiple matching rows should have returned NotSingleRowError")
 	}
+
+	_, err = conn.SelectValue("select 'Matthew', 'Mark'")
+	if _, ok := err.(UnexpectedColumnCountError); !ok {
+		t.Error("Multiple columns should have returned UnexpectedColumnCountError")
+	}
 }
 
 func TestSelectValues(t *testing.T) {
@@ -262,4 +267,9 @@ func TestSelectValues(t *testing.T) {
 	test("select * from (values ('Matthew'), ('Mark'), ('Luke'), ('John')) t", []interface{}{"Matthew", "Mark", "Luke", "John"})
 	test("select * from (values ('Matthew'), (null)) t", []interface{}{"Matthew", nil})
 	test("select * from (values (1::int4), (2::int4), (null), (3::int4)) t", []interface{}{int32(1), int32(2), nil, int32(3)})
+
+	_, err := conn.SelectValues("select 'Matthew', 'Mark'")
+	if _, ok := err.(UnexpectedColumnCountError); !ok {
+		t.Error("Multiple columns should have returned UnexpectedColumnCountError")
+	}
 }