Who knows Conan's real identity?

There are currently 10 persons who know Conan's real identity (at the time of writing).

They are, in order of "discovery":

1. Professor Hiroshi Agasa: in Volume 1

2 & 3. Shinichi's parents: in Volume 6

4. Heiji Hattori: in Volume 13

5. Ai Haibara: in Volume 18

6. Eisuke Hondou: in Volume 61

7. Kaitou Kid: in the 3rd Movie (The Last Wizard of the Century)

8. Sharon Vineyard: in Episode 286 to 288

9. Akemi Miyano: in File 621

10. Hiroki Sawada: in the 6th Movie (The Phantom of Baker Street)

Source: Detective Conan Wiki (List of characters who know Conan's identity)