Police said 28-year-old Gustavo Guzman-Perez was last seen around 2 a.m. on Saturday in McHenry in the 1200 block of North Green Street.
Guzman-Perez is considered to be "at-risk." Authorities asked anyone with information on Guzman-Perez's whereabouts to call 911 or McHenry police.
Police did not immediately provide further information.