The Kartikai festival is held in several places in South India in the month of Kartik (November-December). The festival is of special importance in Andhra Pradesh and Tamil Nadu. It is celebrated in the Tamil month of Karthikai, when the constellation Karthikai appears. It corresponds to the Malayalam month of Vrischikam.

Lord Karthikeyan or Lord Muruga, is one of the favourite deities of the Tamil Brahmins. Kartikai is celebrated in honour of the appearance of Shiva as a fiery Lingam at the birth of the universe. The residents say, the festival also celebrates the filial bond and brothers present gifts to their sisters who wish for their well being. It is believed; the hilI of Arunachala in South India is itself the Lingam. A beacon lit here is the signal for the start of the celebrations of the Kartikai festival and the beacon burns for many days. The sacred hill attracts pilgrims in large numbers from all over South India during the festival.

The city prepares itself to receive lakhs of visitors on the Deepam day. In the temple, the preparation for the festival begins with the Pandalkal Muhurtham, a simple ceremony held to mark the commencement of the various arrangements. Invitations are printed and distributed and arrangements for flowers, erection of thatched sheds for shops, and for providing resting places for the pilgrims are made. Lord`s premises are cleaned. Voluntarily, devotees take upon themselves the task of removing the cobwebs and washing the enclosures around the sanctum. Many of the gold and silver ornaments and vessels are polished under the watchful eyes of the temple authorities. The copper cauldron in which the deepam is lit is taken out and cleaned.

Rice is offered to Lord Shiva on this occasion. Special dishes made of rice and various pulses mixed with jaggery are offered as `Neyvedhyam` (offering of food to god). A noteworthy feature being that the dishes generally make use of jaggery. However, during festivals like Deepavali, they are sweetened with sugar. The `Neyvedhyam` is placed in front of the elephant lamp, which then is placed with the cluster of lights, which are lit, in front of the house.

Thus, the main festival is of ten days` duration only. The first day begins with the hoisting of the flag, called dwajarohanam. It marks the beginning of any temple festival. But, large crowds attend the dwajarohanam of the Karthigai Deepam festival. On the night of the fifth day, the Lord with His consort is taken on his mount, the Rishaba (the bull) made of silver. The eighth day festival is the day of the Maha Ratham (great chariot car) when Lord Arunachala and Goddess Unnamalai are taken round the main streets along with the other deities each in their own chariot. The tenth day festival marks the climax. On the previous night, the people to prepare the temple for the Bharani Deepam clear the temple premises. The significance of Bharani Deepam is that the universal Lord manifests as the five elements and during the evening, He again becomes the One Entity and shines as tejolinga when the deepam is lit atop the Hill.

The deepam burns for seven, nine, eleven or thirteen days and at about six every evening it flares up and burns throughout the night. During these few nights it is a rare experience to perform giripradakshina. People circumambulate the hill of Arunachal. The other important temples where the Karthikai festival is celebrated are Chidambaram, Madurai, Kanchipuram, Thanjavur in Tamil Nadu and Sri Kalahasti in Andhra Pradesh.