Pneumatosis cystoides intestinalis (PCI) is a rare disease that involves the presence of gas in the intestinal wall. Connective tissue disease (CTD) is a major cause of secondary PCI. In addition to the nature of CTDs, the use of prednisolone and some immunosuppressants, and the presence of complicating diseases such as diabetes mellitus, constipation and pulmonary diseases are involved in the development of PCI. This report describes four cases of PCI with different CTDs (granulomatosis with polyangiitis, rheumatoid arthritis, dermatomyositis, and overlap syndrome) and discusses the background of each patient and common risk factors for the occurrence of PCI.