Background: Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection in organ transplant recipients that may be prevented by antibiotic prophylaxis. We aimed to investigate the incidence rate (IR) of PCP and the related hospitalization and mortality rates in liver transplant recipients in an era of routine prophylaxis. Methods:We included all adult liver transplant recipients transplanted at Rigshospitalet between January 1, 2011 and October 1, 2019. Microbiology data were obtained from the Danish Microbiology Database (MiBa), a national database containing all data from all Departments of Clinical Microbiology in Denmark receiving samples from both hospitals and general practices.According to local guidelines, PCP prophylaxis was initiated 1 week posttransplantation and discontinued after 6 months or sooner in patients experiencing side effects. Results: We included 343 liver transplant recipients with 1153 person-years of follow-up (PYFU), of which 269 (78%) received PCP prophylaxis during the first 6 months posttransplantation. Seven (2%) recipients were diagnosed with PCP during follow-up. In the first 6 months posttransplantation and in 269 transplant recipients who received prophylaxis there were zero PCP events while the IR was 32 (95% confidence interval [CI] 2.9-148) per 1000 PYFU in 74 recipient who did not receive prophylaxis. During 7th to 12th month posttransplantation the IR was 20 (95% CI: 5.5-53) per 1000 PYFU. All seven (100%) recipients diagnosed with PCP were hospitalized, however none died.