Amid blowing of conch shells and chants of vedic hymns, worshippers offered prayers since early morning in temples which wore a festive look.
In Mumbai, youngsters went around the city in processions and broke 'dahi handi' (pot filled with butter or curd and tied to a rope as high as 40-ft).
The faithful formed pyramids at various places to reach the handi as those gathered attempted to thwart their efforts by splashing water on them.
Devotees observed day-long fasts as special delicacies for the occasion remained an attraction.
Amid tight security, over ten lakh pilgrims paid obeisance at temples in Mathura where the deity is believed to have been born.
"The celebrations started this morning after bathing Krishna ji with water from the Yamuna. A special Abhishek (bathing the deity) was performed amid chanting of Vedic hymns, beating of drums and playing of musical instruments," said Dinesh Chandra Goswami, a priest at the Radha Raman temple.
Janmashtami was also celebrated in temples of nearby towns of Vrindavan, Baldeo and Goverdhan.
In Jammu and Kashmir, long-winding queues were seen outside lit-up temples as fervour marked the festivities.
Raghunath rath yatras, some with tableaux depicting various aspects of the life of Lord Krishna, were also taken out in various parts of Jammu in which hundreds participated.
