Balaji Jayanti is observed on Margashira Krishna Ashtami, eighth day after Full Moon in Margashirsha month, as per Telugu Calendar followed in Andhra Pradesh.
And in many places and as per many traditions, Venkateshwara Swamy Jayanti is observed on Shravana Nakshatra in Shravana Masam (August 2, 2012). It is believed that on this day Lord Balaji (Venkateshwara swamy) was born to Vakula Mata.
In some places, Balaji Jayanti is celebrated on December 12.
Maha Aarati is the popular ritual observed on Balaji Jayanti in world famous Tirumala Tirupati temple of Lord Venkateshwara. Several lakhs of devotees visit the Lord on this day for Maha aarati puja.
As per Margashira Krishna Ashtami Sampradaya, Balaji Jayanti 2013 date is January 5.