A cat registration number is a unique number assigned to a cat at the time it is registered with the Cat Fanciers Association (CFA) . This number serves two purposes: to identify the cat and to track its pedigree. The registration number is assigned to the cat for life and cannot be transferred to another cat.

It is important to note that the term "CAT registration number" can also refer to the registration number assigned to candidates who register for the Common Admission Test (CAT), an entrance exam for admission to management programs in India. In this case, the registration number serves as a unique identification number assigned to each candidate who registers for the exam.

The CAT registration number is also known as the user ID, and it is the same for all candidates who register for the exam. Candidates need this registration number to access the CAT IIM portal, where they can fill out the application form, complete the payment, and download the admit card and result. The registration number is sent to the candidates registered email ID or phone number after they complete the registration successfully.