Six persons went to the bank of Kharun river for picnic, they said, adding four of them got into the water for bathing.
When one of them started drowning, the other three went to rescue him but all the four persons drowned, they said.
On receiving information, police reached the spot and with the help of divers the four bodies were fished out, they said.
The deceased were identified as 21-year-old Subham Sinha, Shahrukh (22), Sujat and Kshitij Singh (both 17), the police said.
Later, Chhattisgarh Chief Minister Raman Singh expressed grief over the death of the four men, senior officials said.