Udyog Aadhaar Registration, officially known as Udyog Aadhaar Memorandum (UAM), was the earlier MSME registration system introduced by the Ministry of Micro, Small and Medium Enterprises in 2015. It allowed eligible businesses to register using their Aadhaar details and receive a 12-digit Udyog Aadhaar Number (UAN). The UAN followed a format such as DL05A0000001, consisting of two letters, two digits, one letter, and seven digits.

It is important to note that Udyog Aadhaar Registration and Udyog Aadhaar Memorandum (UAM) refer to the same earlier MSME registration system. But Udyog Aadhaar Registration is the commonly used name for the UAM one page online registration system.

The earlier Udyog Aadhaar system was based on self-declared information, which made MSME registration simple. However, it offered less integration with government databases and other digital government systems. To provide a more integrated registration process, the Government of India introduced Udyam Registration on 1 July, 2020, replacing the earlier Udyog Aadhaar Memorandum (UAM) system.

Udyam Registration is also based on self-declaration but is integrated with government databases. The applicable investment and turnover details are automatically obtained from government databases using PAN and GST information.

Today, Udyam Registration is the current MSME registration system. If you are registering your business for the first time, you can apply for Udyam Registration. If you already have an old Udyog Aadhaar / UAM, you can use the UAM to Udyam Migration process instead.