The Garbha Gruha or sanctum is where the main idol of Lord Sri Venkateswara resides. The idol stands majestically in the Garbha Gruha, directly beneath a gilt dome called the Ananda Nilaya Divya Vimana.
This exquisitely-wrought idol called the Mulaberam, is believed to be self-manifested, as there has been no known sculptor possessing the capability to sculpt idols so proportionately and beautifully. Further, no human being is known to have installed it in the shrine.
Ordinarily, the Lord wears a gold kiritam which has a large emerald embedded in front. On special occasions, he is adorned with a diamond kiritam.
On his forehead, the Lord has a thick double patch of upwrought namam drawn with refined camphor, which screens his eyes. In between the two white patches is a kasturitilakam.
His ears are bedecked with shining golden makara kundalas. The fist of His raised right hind hand is implanted with a gem-set chakra, and the corresponding left fist with the sankhu. The slightly outstreched front right hand, has its fingers pointing to His lotus feet, as the only recourse to His devotees to attain oneness with Him and enjoy eternal bliss. His front left hand is akimbo to assure His devotees of protection, and to show that the samsara sagara is only hip-deep if they seek His refuge.
His body is clothed with a pitambaram tied with gold string, and a gold belt to which are attached tiny, jingling gold bells. He is adorned with precious ornaments. He has a yajnopavita flowing down cross-wise from His left shoulder. He bears Sri Lakshmi Devi on His right chest and Sri Padmavathi Devi on His left chest. He bears Nagabharanam ornaments on both shoulders.
His lotus feet are covered with gold frames and decked with clinging gold anklets. A strong curved belt of gold encompasses his legs.
During Abhishekam, we can have darshan of Goddess Lakshmi.
The Ananda Nilaya Divya Vimana was covered with gilt copper plates and surmounted with a golden vase, in the thirteenth century, during the reign of the Vijayanagara king, Yadava Raya.
Pilgrims are not allowed to enter the Garbha Gruha (beyond Kurasekara path)