UN agency, the International Telecommunication Union expects the number of mobile phone subscriptions globally to reach five billion in 2010.
The ITU says growth is driven by advanced services and handsets in developed countries and increased take-up of mobile health services and mobile banking in the developing world.
The body said there were around 4.6 billion mobile cellular subscriptions by the end of 2009.
"Even during an economic crisis, we have seen no drop in the demand for communications services," ITU Secretary-General Dr Hamadoun Touré, said at in the Mobile World Congress in Barcelona this week. "I am confident that we will continue to see a rapid uptake in mobile cellular services in particular in 2010, with many more people using their phones to access the Internet," he said.
"Good examples include sending reminder messages to patient's phones when they have a medical appointment, or need a pre-natal check-up," Toure said. "Or using SMS messages to deliver instructions on when and how to take complex medication such as anti-retrovirals or vaccines." People with no bank accounts are now also able to carry out financial transactions with their phones in developing countries, he said.