Reasons for the decline of the Maurya empire:

(i) Soon after the death of Ashoka, who was the most efficient and powerful administrator of the Maurya empire, the empire broke into two parts. The eastern part of the empire came in the hands of the king Dasaratha, and the western part of the empire came under the control of Sampati.

(ii) It is believed that Ashoka under the influence of Buddhism became a pacifist and weakened his army. It is also believed that the religious policy of Ashoka antagonised the brahmanas as he banned the animal sacrifice, which affected the economic and religious activities of the brahmanas. Because of this, Pusyamitra, the brahmana chief of the Maurya army, killed the last Mauryan king. But this does not seem to be correct as it is evident from the Ashokan inscriptions that Ashoka paid full respect to Brahmanas.

Moreover there is no doubt that Ashoka followed a policy of peace and harmony, but he did not disband his army and was always prepared to face any eventuality.

(iii) Succession of weak rulers is considered as one of the main reasons for decline. These rulers could not keep under check those ministers and officials of far-flung regions, who had become oppressive and acted against the interest of the centre.

(iv) It is also possible that Mauryan rule may have suffered some kind of economic crisis. It is reflected in the debasement of some coins of that period. This crisis might have developed either due to massive donations and charity or overspending on the imperial administrative system.

(v) In fact, the reason for decline was inherent in the structure of the vast centralised empire itself. The successors of Ashoka could not maintain the balance between the centre and the various provincial governors of the empire, and at the first possible opportunity, they made an effort to separate themselves from the centre.