Use VarToDateTime instead. It supports many more date formats in the string and converts them automatically.
var DateVal: TDateTime; begin DateVal := VarToDateTime('23 Sep 2010'); ShowMessage(DateToStr(DateVal)); end;
I see you’re using Delphi 5. Some versions of Delphi will need to add Variants to the uses clause; most later versions add it for you. I don’t remember which category Delphi 5 fell into.