BackgroundOpportunistic infections associated with immunosuppressive treatments for inflammatory bowel disease pose an important safety concern. Here we report the case of a patient with active ulcerative colitis and cryptococcal pneumonia who was treated with vedolizumab combined with fluconazole.Case presentationA 56-year-old Japanese man with ulcerative colitis and a history of Sweet’s syndrome who was taking prednisolone and azathioprine presented with a moderate exacerbation of ulcerative colitis, abdominal pain, diarrhea, and bloody stools along with cytomegalovirus infection. Increasing the prednisolone dose without using antiviral drugs improved cytomegalovirus infection; however, ulcerative colitis did not improve, and cryptococcal pneumonia occurred. Thus, treatment with fluconazole followed by vedolizumab was initiated for ulcerative colitis. The patient gradually recovered and achieved clinical remission without the exacerbation of pneumonia.ConclusionsWe reported the first case of a patient with ulcerative colitis who was treated with vedolizumab and concomitant fluconazole for active cryptococcal pneumonia. Vedolizumab constitutes a high-potential treatment regimen owing to its safety in inflammatory bowel disease associated with opportunistic infections.