Purpose: To report 20 cases with implant periapical pathology diagnosed during the osseointegration phase, evaluating retrospectively the efficacy of the treatment with implant periapical surgery. Materials and Methods: A retrospective chart review was conducted of all patients in whom implant periapical surgery was performed between 1996 and 2010. The criteria for diagnosing implant periapical pathology and, accordingly, performing implant periapical surgery were: (1) acute pain during the osseointegration period (8 weeks after implant placement) located in the area of the affected implant or presence of mucous fistula in relation with the implant apex; (2) absence of implant mobility; (3) non-dull percussion of nonsubmerged implants; and (4) presence or absence of implant periapical radiolucency. Results: Twenty-two implants were diagnosed with periapical pathology in 20 patients (13 women and 7 men) with a mean age of 54.3 years (range, 32 to 70 years) and were consecutively treated by a surgical approach. In 19 implants, the diagnosis was acute apical peri-implantitis (nonsuppurated in 7 cases and suppurated in 12), as based on the symptoms and radiographic sign, and in 3 cases it was subacute apical peri-implantitis, as based on the presence of a fistula. After a minimum follow-up of 1 year, 20 implants remained functional, with no clinical or radiologic alterations; the survival rate of the treated implants was 91%. Conclusion: The early diagnosis of inflammatory implant periapical lesions during the osseintegration phase, and their prompt surgical treatment, led to a survival rate of the treated implants of 91%. Keywords: implant periapical lesion, retrograde peri-implantitis, apical surgery, dental implants