90-year-old Bush, a Texas resident, was admitted to Houston Methodist Hospital last evening as a precaution, his spokesman Jim McGrath said in a statement.
McGrath says Bush "will be held for observation, again as a precaution."
The 41st president spent nearly two months in the same hospital and was discharged in January 2013 after treatment for a bronchitis-related cough and other health issues.
Bush, who can no longer use his legs, most recently appeared seated in a wheelchair at an event in November at Texas A&M University with his son George W Bush, also a former President.