diff --git a/gorp_test.go b/gorp_test.go
index b135fff..e3b3693 100644
--- a/gorp_test.go
+++ b/gorp_test.go
@@ -1720,7 +1720,7 @@ func TestColumnFilter(t *testing.T) {
 	}
 }
 
-func TestTypeConversionExample(t *testing.T) {
+func TestTypeConversionDBMapExample(t *testing.T) {
 	dbmap := initDBMap(t)
 	defer dropAndClose(dbmap)
 
@@ -1821,12 +1821,13 @@ func TestTypeConversionExample(t *testing.T) {
 		t.Errorf(`Select failed: %s`, err)
 	}
 
-	_, err = dbmap.QueryContext(context.Background(),
+	rows, err := dbmap.QueryContext(context.Background(),
 		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
 		personJSON, hi2)
 	if err != nil {
 		t.Errorf(`Select failed: %s`, err)
 	}
+	_ = rows.Close()
 
 	row := dbmap.QueryRowContext(context.Background(),
 		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
@@ -1847,6 +1848,155 @@ func TestTypeConversionExample(t *testing.T) {
 	}
 }
 
+func TestTypeConversionTransactionExample(t *testing.T) {
+	dbmap := initDBMap(t)
+	defer dropAndClose(dbmap)
+
+	p := Person{FName: "Bob", LName: "Smith"}
+	tc := &TypeConversionExample{-1, p, CustomStringType("hi")}
+	_insert(dbmap, tc)
+
+	expected := &TypeConversionExample{1, p, CustomStringType("hi")}
+	tc2 := _get(dbmap, TypeConversionExample{}, tc.Id).(*TypeConversionExample)
+	if !reflect.DeepEqual(expected, tc2) {
+		t.Errorf("tc2 %v != %v", expected, tc2)
+	}
+
+	hi2 := CustomStringType("hi2")
+	tc2.Name = hi2
+	tc2.PersonJSON = Person{FName: "Jane", LName: "Doe"}
+	_update(dbmap, tc2)
+
+	expected = &TypeConversionExample{1, tc2.PersonJSON, CustomStringType("hi2")}
+	tc3 := _get(dbmap, TypeConversionExample{}, tc.Id).(*TypeConversionExample)
+	if !reflect.DeepEqual(expected, tc3) {
+		t.Errorf("tc3 %v != %v", expected, tc3)
+	}
+
+	d := dbmap.Dialect
+	pj := d.QuoteField("PersonJSON")
+	id := d.QuoteField("Id")
+	name := d.QuoteField("Name")
+	bv0 := d.BindVar(0)
+	bv1 := d.BindVar(1)
+
+	// Test that the Person argument to Select goes through the
+	// type converter
+	var holder TypeConversionExample
+	personJSON := Person{FName: "Jane", LName: "Doe"}
+	ctx := context.Background()
+	tx, err := dbmap.BeginTx(ctx)
+	if err != nil {
+		t.Errorf("begin tx: %v", err)
+		return
+	}
+	defer tx.Rollback()
+
+	_, err = tx.Select(ctx,
+		holder,
+		`select * from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	err = tx.SelectOne(ctx,
+		&holder,
+		`select * from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectInt(ctx,
+		`select `+id+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectInt(ctx,
+		`select `+id+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectNullInt(ctx,
+		`select `+id+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectFloat(ctx,
+		`select `+id+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectNullFloat(ctx,
+		`select `+id+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectStr(ctx,
+		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	_, err = tx.SelectNullStr(ctx,
+		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	rows, err := tx.QueryContext(ctx,
+		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+	_ = rows.Close()
+
+	row := tx.QueryRowContext(ctx,
+		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if row == nil || row.Err() != nil {
+		t.Errorf(`QueryRowContext failed: %s`, row.Err())
+	}
+	// Must consume the row to release the connection.
+	var gotName string
+	err = row.Scan(&gotName)
+	if err != nil {
+		t.Errorf(`QueryRowContext failed: %s`, err)
+	}
+
+	_, err = tx.ExecContext(ctx,
+		`select `+name+` from type_conv_test where `+pj+`=`+bv0+` and `+name+`=`+bv1,
+		personJSON, hi2)
+	if err != nil {
+		t.Errorf(`Select failed: %s`, err)
+	}
+
+	// We must rollback to release the transaction's connection before we can
+	// delete the row below.
+	err = tx.Rollback()
+	if err != nil {
+		t.Errorf("rollback failed: %v", err)
+	}
+
+	if _del(dbmap, tc) != 1 {
+		t.Errorf("Did not delete row with Id: %d", tc.Id)
+	}
+}
+
 func TestWithEmbeddedStruct(t *testing.T) {
 	dbmap := initDBMap(t)
 	defer dropAndClose(dbmap)
diff --git a/transaction.go b/transaction.go
index 27eecc4..33e2717 100644
--- a/transaction.go
+++ b/transaction.go
@@ -51,6 +51,11 @@ func (t *Transaction) Select(ctx context.Context, i interface{}, query string, a
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return nil, err
+	}
+
 	return hookedselect(ctx, t.dbmap, t, i, query, args...)
 }
 
@@ -60,6 +65,11 @@ func (t *Transaction) ExecContext(ctx context.Context, query string, args ...int
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return nil, err
+	}
+
 	if t.dbmap.logger != nil {
 		now := time.Now()
 		defer t.dbmap.trace(now, query, args...)
@@ -73,6 +83,11 @@ func (t *Transaction) SelectInt(ctx context.Context, query string, args ...inter
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return 0, err
+	}
+
 	return SelectInt(ctx, t, query, args...)
 }
 
@@ -82,6 +97,11 @@ func (t *Transaction) SelectNullInt(ctx context.Context, query string, args ...i
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return sql.NullInt64{}, err
+	}
+
 	return SelectNullInt(ctx, t, query, args...)
 }
 
@@ -91,6 +111,11 @@ func (t *Transaction) SelectFloat(ctx context.Context, query string, args ...int
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return 0, err
+	}
+
 	return SelectFloat(ctx, t, query, args...)
 }
 
@@ -100,6 +125,11 @@ func (t *Transaction) SelectNullFloat(ctx context.Context, query string, args ..
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return sql.NullFloat64{}, err
+	}
+
 	return SelectNullFloat(ctx, t, query, args...)
 }
 
@@ -109,6 +139,11 @@ func (t *Transaction) SelectStr(ctx context.Context, query string, args ...inter
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return "", err
+	}
+
 	return SelectStr(ctx, t, query, args...)
 }
 
@@ -118,6 +153,11 @@ func (t *Transaction) SelectNullStr(ctx context.Context, query string, args ...i
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return sql.NullString{}, err
+	}
+
 	return SelectNullStr(ctx, t, query, args...)
 }
 
@@ -127,6 +167,11 @@ func (t *Transaction) SelectOne(ctx context.Context, holder interface{}, query s
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return err
+	}
+
 	return SelectOne(ctx, t.dbmap, t, holder, query, args...)
 }
 
@@ -211,6 +256,11 @@ func (t *Transaction) QueryRowContext(ctx context.Context, query string, args ..
 		expandSliceArgs(&query, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return nil
+	}
+
 	if t.dbmap.logger != nil {
 		now := time.Now()
 		defer t.dbmap.trace(now, query, args...)
@@ -223,6 +273,11 @@ func (t *Transaction) QueryContext(ctx context.Context, q string, args ...interf
 		expandSliceArgs(&q, args...)
 	}
 
+	args, err := t.dbmap.convertArgs(args...)
+	if err != nil {
+		return nil, err
+	}
+
 	if t.dbmap.logger != nil {
 		now := time.Now()
 		defer t.dbmap.trace(now, q, args...)