Patient deaths or disabilities resulting from surgery or falls also rose.
The state Public Health Department says reports of wrong-site surgeries in Connecticut hospitals increased by 62 percent last year, while the number of patient deaths or disabilities resulting from surgery or falls also rose.
The report that covers 2011 also says reports of patients suffering from serious pressure ulcers - or bed sores - declined 39 percent.
The Adverse Event Report says reports of patients who had surgery performed on the wrong body part increased from eight in 2010 to 13 last year.
Ninety-six patients died or were seriously injured from falls in 2011 - up from 91 the year before.
Dr. Mary Reich Cooper, vice president and chief quality officer for the Connecticut Hospital Association, tells The Courant of Hartford that hospitals are working together to eliminate errors.