Background: Isavuconazole, administered as isavuconazonium sulfate (ISAVUSULF), is a broad-spectrum triazole agent for the treatment of invasive fungal disease. In phase 3 studies, ISAVUSULF showed comparable efficacy to voriconazole and amphotericin B for the treatment of invasive aspergillosis (IA) and invasive mucormycosis (IM), respectively. Objectives: The objective of this study is to determine all-cause mortality and safety outcomes among adults with IM and/or IA non-fumigatus (nf) treated with ISAVUSULF or other antifungal therapies (AFT). Patients and methods: This multicentre, non-interventional registry enrolled patients aged ≥18 years with IM or IA-nf who received systemic AFT from January 2016 to November 2018. Patients received primary ISAVUSULF, non-primary ISAVUSULF, or other AFT, as monotherapy or combination therapy. The primary end point was all-cause mortality at Days 42 and 84; safety outcomes were adverse drug reactions (ADRs) to ISAVUSULF. Results: Of 204 patients enrolled, 74 received primary ISAVUSULF, 30 non-primary ISAVUSULF, and 100 other AFT. All-cause mortality through Day 42 was numerically lower in the non-primary ISAVUSULF group than in the primary ISAVUSULF and other AFT groups, for patients with IM (20.0% vs. 33.3% and 41.3%, respectively) or IA-nf (0% vs. 14.8% and 17.8%, respectively). All-cause mortality tended to be lower with combination therapy than with monotherapy, except for patients with IM receiving primary ISAVUSULF. Of 111 patients receiving ISAVUSULF, 14 (12.6%) reported ADRs, of whom three (2.7%) developed serious ADRs. There were no drug-related deaths. Conclusions: This study supports the effectiveness and tolerability of ISAVUSULF in clinical practice. Further research is required to confirm the value of ISAVUSULF combination therapy over monotherapy.