Vinay Sharma, one of the convicts in the infamous Nirbhaya gang-rape of 2012, attempted suicide in Tihar jail.
Sharma tried hanging himself after consuming pills, a report said.
He was admitted to Deen Dayal Upadhyay Hospital in the national capital.
Ram Singh, the main accused in the case, had committed suicide by hanging himself in the jail in 2013.
On the night of December 16, 2012, Ram Singh, Vinay Sharma, Akshay Thakur, Pawan Gupta, Mukesh and a juvenile had gang-raped a girl in a bus and beaten up her 28-year-old male friend, who was with her.
While the girl succumbed to her injuries on December 29, 2012 at a Singapore hospital, the victim's friend, suffered grievous injuries in the incident.
The juvenile accused was on August 31, 2013 convicted and sentenced to three years in a reformation home, while four others were handed down death penalty.