Reusing syringes leads to more than two million people being infected with diseases including HIV and hepatitis each year.
The new needles are more expensive, but the WHO says the switch would be cheaper than treating the diseases.
More than 16 billion injections are administered annually.
Normal syringes can be used again and again.
But the smart ones prevent the plunger being pulled back after an injection or retract the needle so it cannot be used again.
Dr Selma Khamassi, the head of the WHO team for injection safety, told the BBC News website: “This will hopefully help eliminate the 1.7 million new hepatitis B cases, the 300,000 hepatitis C cases and the 35,000 HIV cases every year, and all those we don’t have figures for, such as Ebola and Marburg.”
Standard syringes cost between two cents (1.3p) and four cents. The smart syringes cost between four and six cents.
The WHO describes it as a “small increase”. However, the tiny difference in the price of one needle becomes huge when it is scaled up to 16 billion injections.
Dr Khamassi added: “Injection safety is, I think, the most cost-effective way to prevent all these diseases.
“If we compare the price of most expensive syringes to the cost of treatment for an HIV case, or a hep C case, there is no comparison.”
The WHO is also calling for sheathed needles that prevent doctors accidentally pricking their fingers.
This has happened many times during the Ebola outbreak in West Africa.
But they would treble the cost of the syringes and the WHO says these would have to be introduced “progressively”.
The WHO is calling on industry to expand production and find ways of reducing the cost of the safer needles.
Marc Koska, head of Safepoint – which campaigns to stop the reuse of syringes – told the BBC: “It’s totally, totally possible.
“We’ve already done this with immunisation, which represents less than 10% of the injections given in the developing world, and that has been a fantastic success.
“Now we’re targeting the 90% of what we call curative injections.”