Prosecutor Ujjwal Nikam says he asked for the death sentence under a strict anti-rape law introduced in India last year.
The three men were found guilty last month of raping a call-center operator at the same abandoned mill. Nikam described the three as habitual offenders.
India increased penalties for sex crimes after public anger followed the fatal rape of a 23-year-old medical student in December 2012 in New Delhi. Four men were sentenced to death in the New Delhi case.
Also Friday, 24 men were sentenced to prison for raping a teenager in Kerala state in 1996.