The main differences between departmental organisations, public corporations and Government companies are as follows:

1. Departmental organisations are the oldest form of state enterprises, whereas public corporations and Government companies are the modem forms of state enterprises. 

2. A departmental organization is not governed under any act. A public corporation governed under a special act. A Government company is governed under the Companies Act. 

3. A departmental organization does not have a separate legal entity. A public corporation has a separate legal entity.

4. A departmental organization cannot borrow funds from the public. On the other hand, a public corporation and a Government company can borrow funds from the public. 

5. A departmental organization is established by ministry. A public corporation established by ministry. A Government company is established by the Government or by the government and private investors. 

6. A departmental organisation is liable to more political interference than a public corporation and a government company. 

7. A departmental organisation is subject to more Government control in respect of accounting, audit, etc. than a public corporation and a government company. 

8. A departmental organisation does not enjoy flexibility of operations. A public corporation has considerable flexibility. A government company has enough flexibility. 

9. Departmental organisations and public corporations have more public accountability than the Government companies. 

10. Departmental organisations are not run on commercial principles. Public corporations are run more with service motive than with profit motive. Government Companies is run purely on commercial principles.