MTN, Africa's biggest mobile operator by subscribers, posted lower 2009 profit despite its new customers increasing by 28% to 116 million.
The country's second-biggest mobile phone operator said on Thursday adjusted headline earnings per share for the year to end-December dropped by 16.6% to 754.3 cents.
Headline EPS is the main profit gauge in South Africa and strips out certain one-off, financial and non-trading items.
The group said adjusted headline EPS, excluding the impact of functional currency losses, was up 8.5% to 878.9 cents.
"Movements in exchange rates in the year, mainly in the South African rand and Nigerian naira, had a substantially negative impact on the group's financial results," said Phuthuma Nhleko, chief executive officer of MTN, who will step down as CEO and group president in March 2011.
MTN, which operates mobile phone networks across Africa and the Middle East, said revenue grew 9.2% to 111.9 billion rand (USD 15.08 billion).
MTN may face tougher competition from its rival, Kuwait's Zain, in Africa as India's Bharti Airtel seeks to buy Zain's African mobile operations for USD 10.7 billion.
