The collision occurred just after 1 a.m. at 17th and G streets, said San Diego police Officer David Stafford.
A 53-year-old man drove a Dodge Dakota pickup truck southbound on 17th Street in front of a 24-year-old man in an Acura Integra who was eastbound on G Street when the two vehicles collided, Stafford said.
The 53-year-old man suffered a broken back and broken ribs, the officer said.
The 24-year-old man suffered fractured vertebrae and a fractured sternum. Both were transported to trauma centers for treatment of non-life threatening injuries, he said.
The Dakota driver will be booked on suspicion of felony DUI, Stafford said. The Acura driver will be booked on suspicion of misdemeanor DUI.