As the Abbasid government rulers' pressure on Imam Hasan Al-Askari (AS) and his family was tremendous, the disclosure of Imamate of Imam Mahdi (AS) was among the near circle of the most trusted persons. Imam Hasan Al-Askari (AS) told very few most trusted believers and allowed them to see his successor Imam Al-Mahdi (AS). These are names of some of those who saw Imam Al-Mahdi (AS):

1. Othman ibn Sa'eed Al-Amri who became later the first Safeer of the Imam Al-Mahdi (AS).

2. Muhammad ibn Othman ibn Sa'eed Al-Amri, who became later the second Safeer of the Imam.

3. Al-Husain ibn Rooh.

4.  Ali ibn Muhammad Al-Samari.

5. Lady Hakimah daughter of Imam Al-Jawad (AS).

6. Ibraheem ibn Mahziyar Al-Ahwaazi.

7. Ahmad ibn Eshaq ibn Sa'd Al-Ash'ari.

8. Ahmad ibn Muhammad ibn Al-Mutahhar.

9. Ismael ibn Ali Al- Nawbakhti.

10. Ali ibn Ibraheem ibn Mahziyaar Al-Ahwaazi.

11.Kaamil ibn Ibrahim Al-Madani.

12.Allaan Al-Kulayni.

13. Muhammad ibn Ismael ibn Musa Al-Kadhim.

14. Al-Hasan ibn Wajnaa' Al-Naseebi.

15.Ibrahim ibn Idrees.

16. Ibrahim ibn A'bdah Al-kNisabori.

17.Ibrahim ibn Muhammad Al-Tabreezi.

18. Sa'ad ibn Abdullah ibn Abi Khalaf Al-Ash'ari.

19. Ali ibn Muhammad Al-Shimshaati.

20- Muhammad ibn Al-Qasim Al-Aqeeli. 

There are hundreds of well known pious believers who saw Imam Al-Mahdi (AS). Whole books were been compiled on this subject by big scholars.

Wassalam.