Contributor: SWAG SUPPORT TEAM { method #1 } unit Unit1; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) ComboBox1: TComboBox; Edit1: TEdit; Edit2: TEdit; procedure Edit1Change(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.DFM} function ComboBox_Item_Exists(ComboBox: tComboBox; str: string): Integer; var i: Integer; begin if ComboBox.Items.Count = 0 then // ComboBox is empty begin Result := -1; // not found Exit; end else for i := 0 to ComboBox.Items.Count -1 do begin if ComboBox.Items[i] = str then begin Result := i; // eureka // str at pos i in ComboBox Exit; // look no further end else Result := -1; // not found end; end; procedure TForm1.Edit1Change(Sender: TObject); begin ComboBox1.ItemIndex := ComboBox_Item_Exists(ComboBox1, Edit1.Text); end; end. What do you think about this replace ? function ComboBox_Item_Exists(ComboBox: tComboBox; str: string): Integer; begin Result := ComboBox.Items.IndexOf( Str ); end;