The exam is held at 1,026 centres across the India. The results will be announced on May 26.
The students qualifying the test will be eligible for admission into B.Tech programmes in these institutes offering over 10,000 seats.
"The number of candidates has gone up to 4.72 lakh this year against four lakh candidates last year," Prof T S Natarajan, Organising Chairman, JEE 2010, said.
The test comprises two sessions. The first session started at 9 am and will continue till 12 while the second session will start from 2 pm. The papers will have questions on Physics, Chemistry and Mathematics.
The IITs have decided to conduct on-line counselling for general category students this year.
However, the OBC candidates will have to go to the exam centres for counselling where their certificates will be examined.