He’s sleeping like a baby and doesn’t like it.

A Rikers Island inmate is suing the city because his prison bed — which he claims is too short for his 6-foot-1 frame and forces him to curl up in a fetal position every night — is causing “extreme lower-back pain.”

Maxie Leak’s lawsuit in Manhattan federal court alleges that the Department of Corrections refuses to provide longer beds because of cost.

“When I lay down straight, my feet hang out the bottom of the bed, so I am forced to lay down in a compromised position,” Leak, 43, wrote in his suit.

“This position, known as fetal, has taken a toll on me and has caused me extreme lower-back pain.”

Leak, who has been held at Rikers since August on a third-degree felony burglary charge, insists that he decided to sue only as a last resort.

“I have complained to all I could in order to get a longer bed,” he wrote. “My back really hurts badly.”

He’s asking that the city give 6-foot and taller inmates special beds — as well as $1 million in damages.