The incident took place on Saturday evening when two sisters, aged 14 and 7, went to their fields. They were picked up by five men, belonging to the same village, who took them to an isolated location, they said.
Thereafter, they allegedly raped the elder girl, threw her outside the fields in Tadke village early yesterday morning and fled from the spot, they said.
The younger girl, who was tied with ropes, was asked by the miscreants not to tell about the incident to anyone or else they would kill her, police said.
The girls' family found the elder sister outside the village in an unconscious state, police said, adding that she was sent to a hospital for medical examination.
Upon the complaint by the victims' family, cases have been registered against Virendra Yadav, Makkhu Yadav, Brajbhan Yadav, Kallu Yadav and Dheeru Yadav, all relatives, Kanpur SSP Sarvanand Yadav said.
Police is on the lookout to nab the absconding accused, he said.