Haemophilus is a group of bacteria that causes different types of illness such as breathing, bone and joint disorders and nervous system disorders. Among all the strains of Haemophilus, H infleunzae type b (Hib) is one of the most common types of infecton causing bacteria. The bacteria is also known as Bacillus Influenzae of Pfeiffer's bacillus and it is a gram negative, facultatively, ccobacillary, anaerobic bacteria. This strain of bacterium belongs to the Pasteurellaceae family and was first isolated in 1892 during influenza pandemic. Some strains of the H. infleunzae posses a capsule of polysaccharide and on the basis of different biochemical properties of capsule these strains are classified into 6 different subtypes. Among all the strains of Haemophilus, H infleunzae type b (Hib) is the most virulent strain that is responsible for invasive infections. However, there are some strains of Haemophilus that have no capsule and can be termed as non encapsulated or nontypeable H.infleunzae. This strain of bacteria accounts for more than 95% of the infections occurring due to Haemophilus influenza in adults and children. H. infleunzae is also responsible for wide range of invasive and localized infections which can range from mild ear infection to other sever infections like blood stream infections. This strain can cause cellulitis, meningitis, epiglottis, urinary tract infections, septic arthritis, cervical adenitis, endocartis, osteomyelitis and glossitis. Infection caused by non encapsulated H.infleunzae strain includes sinusitis, pneumonia, bronchitis, otitis media and mucosal infections.