''Pseudomonas aeruginosa'' is an opportunistic pathogen commonly found in immunocompromised patients.  In addition to being the primary cause of lung infections in cystic fibrosis patients, many severe nosocomial infections can be attributed to ''P. aeruginosa''. Currently, the standard detection method requires a potential sample to be grown overnight and then screened for the pathogen of interest. We have engineered an ''E. Coli'' based biosensor capable of detecting the presence of autoinducer molecules unique to ''P. aeruginosa''. Thus, our system provides a faster detection method without sacrificing reliability or experimental resolution. To realize our objective, we harnessed the native cell signaling and quorum sensing machinery of ''P. aeruginosa''.  Quorum sensing in ''P. aeruginosa'' is a complex hierarchy that governs the expression of numerous virulence genes. Elements of the ''P. aeruginosa'' quorum sensing system were engineered into genetic circuits to detect and discriminate between distinct ''P. aeruginosa'' quorum sensing molecules. We have thus created a novel, inexpensive biosensor capable of detecting the presence of ''P. aeruginosa'' both quickly and effectively.