Abdominal non-tuberculous mycobacterial infection is a rare condition in healthy patients. When it occurs, it leads to the appearance of typical findings of peritoneal involvement, such as thickening of the peritoneal leaflets and the omentum, ascites and enlargement of lymph nodes and of mesenteric nodules. These findings may be misdiagnosed as tumour peritoneal implants. In case of spontaneous regression of the peritoneal involvement and ascites, as well as in the absence of malignancy, the suspicion of infectious disease, including abdominal nontuberculous mycobacterial infection, should be considered.