I Should Have Known Better by The Naturals first appeared on the Israeli foreign-music chart on 31 Aug 1964, entering at #14. It peaked at #5 on 12 Oct 1964. In total it spent 4 weeks on the chart, last charting on 12 Oct 1964.
| Wk | Date | Pos |
|---|---|---|
| 1 | 31 Aug 1964 | 14 |
| 2 | 14 Sep 1964 | 9 |
| 3 | 5 Oct 1964 | 7 |
| 4 | 12 Oct 1964 | 5 |