The results were found during a survey carried out by a healthcare watchdog earlier this year.
The survey found some 467 of the 9,030 patients surveyed -- just over 5pc -- contracted an infection after their admission to hospital.
The survey was conducted by the Health Protection Surveillance Centre as part of a bigger survey about prescribing antibiotics in the hospitals.
The most common infections picked up by patients were surgical wound infections and pneumonia, also known as a chest infection.
Other common infections caught by patients in hospitals were urinary tract infections, including infections of the bladder or kidneys, blood-stream infections, such as MSRA, and gastrointestinal infections, such as gastroenteritis.
The survey found that it was common for patients with these infections to display the common "risk factors", such as having had an operation or having a drip or a bladder catheter put in.
Picking up an infection was more common in patients in intensive care units, older people or very young people.
The survey also found that people who had received antibiotics were more likely to get an infection.
High rates of infections among patients were found in Beaumont Hospital, St Luke's Hospital in Rathgar, Roscommon County Hospital, Tallaght Hospital and St Vincent's in South Dublin.
Dr Robert Cunney, of the Health Protection Surveillance Centre, said it is not possible to directly compare the results between hospitals as they may admit different types of patients and have various medical and surgical personnel working in the hospital.
The best way to stop a patient from getting an infection in a hospital is to ensure proper antibiotic use, good hand washing practice and proper use of intravenous lines and urinary catheters, Dr Cunney said. "Not every infection can be prevented but every effort should be taken to prevent it," he added.