BACKGROUND Actinomycosis is a chronic infectious disease caused by bacteria in the Actinomyces genus. The pathologic, clinic and imagistic polymorphism and the rare incidence of this disease make it so frequent misdiagnosed. MATERIAL AND METHOD Single unit retrospective nonrandomized clinical study on over 40 years of experience in diagnosing and treating abdominal actinomycosis. RESULTS First case of abdominal actinomycosis was diagnosed in our clinic in 1968. During the next 36 years, between 1968 and 2004, there were registered only 3 cases, all ileo-cecal actinomycosis. In the next 3 years interval, 5 more cases were diagnosed: 4 associated with intrauterine devices (IUDs) and 1 associated with intraperitoneal remnant calculi after laparoscopic cholecystectomy. We present these last 5 cases, the first 3 having been reported elsewhere. CONCLUSIONS Abdominal actinomycosis is a rare disease, with variable and deceiving clinical and imagistic characters. In Romania we witness a shift in the epidemiology of this disease as a result of the introducing of the IUDs for the first time after 1990. Confronted with a female patient carrying an IUD that has an inflammatory and a pelvic tumoral syndrome of variable intensity, one should consider also the diagnosis of abdominal actinomycosis. Preoperative establishing of this diagnosis may allow, by a long antibiotic therapy, the elimination of the need for surgery or at least the decrease of its limits. A very rare cause of intraperitoneal actinomycosis is intraperitoneal gallstones remnant after laparoscopic cholecystectomy. To our knowledge, our case is the first reported in the medical literature.