OPAT (Outpatient Parenteral Antibiotic Therapy) arose in the early 1980s in the USA and later in many other countries from the primary consideration that outpatient treatment is more cost-effective than hospitalisation. Currently, several thousand patients undergo OPAT programmes all over the world and several different bacterial infections are included in the list of treatable diseases, especially those requiring long-term parenteral treatment such as osteomyelitis and soft tissue infections. All injectable antibiotics are suitable for OPAT according to their microbiological spectrum, although clearly some pharmacological properties make one antibiotic more preferable than another. Beta-lactams represent more than half of the antibiotic world market and two-thirds of them are cephalosporins. Such a widespread use of cephalosporins is certainly due to their wide antibacterial spectrum and good tolerability. Among third-generation cephalosporins, covering the majority of micro-organisms responsible for community-acquired infections, ceftriaxone is the only one with an 8-hour half-life, thereby permitting a single daily dose, which represents a great advantage when undertaking an OPAT programme. Analysis of antibiotic consumption used for OPAT therapies, based on data collected from the International OPAT Registry project, with the participation of many countries (USA, Canada, Britain, Argentina, etc.) including Italy, shows that ceftriaxone is the most widely used antibiotic for home therapy, clearly due to the above-mentioned properties.