Monobactams are part of the beta-lactam class of antibiotics. Monobactams are naturally occurring, mono-cyclic beta-lactam compounds originally discovered and isolated from Chromobacterium violaceum in the 1970s. These compounds became the focus for antibiotic development due to their ability to disrupt bacterial cell wall biosynthesis. Aztreonam was developed in 1984 and is currently the only monobactam in clinical use. It is a narrow spectrum agent, effective against aerobic, gram-negative pathogens and is most commonly used to treat respiratory and urinary tract infections. It is administered via intravenous or intramuscular routes and features a more favourable side effect profile, with lower nephrotoxicity than other comparable gram-negative antibiotics. This chapter will review the known mechanisms of action of monobactam antibiotics and their relevance to urological practice.