The agency said it found 476 bodies believed to be those of illegal border crossers in the fiscal year that ended Sept. 30, 2012, USA Today reported Saturday. That was up from 380 in 2000.
The patrol has reported 380 bodies since Oct. 1. More deaths tend to occur in the summer, when many would-be immigrants die from thirst and heat exhaustion.
Agents caught 1.7 illegal border crossers in 2000, and the figure fell to 365,000 last year.
Rolando Gutierrez, a deputy in Brooks County, Texas, on the border with Mexico, said he did not realize when he became a police officer that dealing with the bodies of border crossers would be such a big part of the job.
"We've been busier than ever this year," Gutierrez told USA Today. "A lot of people don't know what's happening out here. There doesn't seem to be an end to it."
Guadalupe Correa-Cabrera, who teaches at the University of Texas at Brownsville, said drug cartels have become increasingly involved in moving migrants across the border and are responsible for many of the deaths.
She said she fears increased efforts to catch border crossers will push them into more remote and dangerous areas.