Main objective of this lecture is to describe on Mobile Database. A mobile database is either a stationary database that can be connected to by a mobile computing device – such as smart phones or PDAs – over a mobile network, or a database which is actually carried by the mobile device. Mobile databases need for: Physically separate from the central database server, Resided on mobile devices, Capable of communicating with a central database server or other mobile clients from remote sites and Handle local queries without connectivity. Here also explain some Mobile database Applications.