* 2015 net profit of 393 million euros
* Expects 2016 revenues to stay flat
* Slim, state have to increase free float in 2016 (Adds details, background)
VIENNA, Feb 9 (Reuters) - Telekom Austria, part of Mexican tycoon Carlos Slim's America Movil, returned to profitability in 2015, thanks to growing customer numbers and cost-cutting measures.
The telecommunications group reported a net profit of 393 million euros ($443.78 million), its best result over the past five years. In 2014, it booked a loss of 185 million euros, mainly due to write-downs on its eastern European business.
Customer numbers exceeded 24 million, increasing in Austria, Macedonia, Belarus, Bulgaria, Slovenia and Liechtenstein although the number of mobile customers dropped in Croatia and Serbia, the group said.
Revenue grew 1.3 percent to 4.10 billion euros last year, and Telekom Austria expects a growth rate of around 1 percent in 2016.
"The solid backing provided by the strong partnership between the Federal Republic of Austria and the majority shareholder América Móvil strengthens the management's confidence that the company will continue to pursue the growth path initiated over the past year moving forward," the group said in a statement on Tuesday.
The Mexican company currently controls around 60 percent of Telekom Austria, with 28 percent left in state hands.
When Slim took control in 2014, he agreed to increase the free float of the former state monopoly within two years to at least 24 percent. How this is going to happen is unclear. ($1 = 0.8856 euros) (Reporting by Kirsti Knolle; editing by Susan Thomas and Adrian Croft)