The global health body found that only 19 of 114 countries surveyed had no mobile health initiative, known as mHealth.
"Eighty three percent are actually saying, yes we are involved with a minimum of one mHealth project," said Misha Kay, who studies cell phone technology for the WHO. But most of those countries have several projects running, he added. "So what we`re seeing is a fairly healthy groundswell of activity, also considering that we believe that a lot of the reports were understated," he said.
With more than five billion cell phone subscribers in the world, and 85 percent of the planet covered by a commercial wireless signal, mHealth is becoming a popular way to strengthen health services.
Speaking at a conference on mobile health in Cape Town, Kay said southeast Asia, the Americas and Europe had the most initiatives but around 75 percent of surveyed African countries were also using the technology.
Globally, the most common schemes for cell phones were call centres or help-lines, emergency toll-free numbers, and mobile telemedicine -- such as doctors consulting one another.
Among the biggest barriers worldwide were cost, a lack of knowledge and health policies that did not recognize mHealth, the study found.
In Africa, the biggest impediments were operating costs and infrastructure, while in Europe concerns centred on the absence of legal guidelines on privacy and confidentiality.
The survey was based on data from a 2009 study by the WHO.