Ageing of the immune system is a complex process involving both humora
l and cell mediated immunity. Along with decline in immunity, morpholo
gical changes in various organ makes the elderly especially vulnerable
to infection. In clinical practice, infections of respiratory tract a
nd urinary tract, endocarditis, septicaemia and tuberculosis are commo
nly encountered in elderly subjects Atypical clinical presentation, sl
ow response to treatment and high mortality are hall marks of infectio
n in order patients. Antibiotic therapy in elderly needs to be early,
empirical and broad spectrum through parenteral route, with early chan
ge over to oral therapy. Aminopenicillins and cephalosporins are safer
drugs in old age as compared to aminoglycosides. Pneumococcal and inf
luenza vaccines are recommended in elderly subjects with medical condi
tions with higher risk of mortality and complications.