Cytomegalovirus (CMV) and invasive aspergillosis (IA) cause morbidity among lung transplant recipients (LTXr). Early diagnosis and treatment could improve outcomes. We examined rates of CMV after IA and vice versa to assess whether screening for one infection is warranted after detecting the other. All Danish LTXr, 2010–2019, were followed for IA and CMV for 2 years after transplantation. IA was defined using ISHLT criteria. Adjusted incidence rate ratios (aIRR) were estimated by Poisson regression adjusted for time after transplantation. We included 295 LTXr, among whom CMV and IA were diagnosed in 128 (43%) and 48 (16%). The risk of CMV was high the first 3 months after IA, IR 98/100 person-years of follow-up (95% CI 47–206). The risk of IA was significantly increased in the first 3 months after CMV, aIRR 2.91 (95% CI 1.32–6.44). Numbers needed to screen to diagnose one case of CMV after IA, and one case of IA after CMV was approximately seven and eight, respectively. Systematic screening for CMV following diagnosis of IA, and vice versa, may improve timeliness of diagnosis and outcomes for LTXr.