Infectious diseases specialists are involved in patient care mostly regarding patients with severe infections in complex situations. Morbidity and mortality of severe infections such as sepsis has been significantly reduced during past years and decades. Prognosis of severe infections is dependent upon timely and correct diagnosis and appropriate therapy. The diagnostic and therapeutic approach is often invasive and interdisciplinary. Importantly, thoughtful use of antibiotics may increase its effectiveness, reduce antibiotic use and occurrence of bacterial resistance and increase cost effectiveness. Hence, antibiotic management and stewardship has become more and more the focus of work. This article highlights the clinical work of infectious diseases specialists in an interdisciplinary setting and describes there value to patients and hospitals.