* Q4 profit 510 mln riyals vs 790.9 mln riyals a yr ago
* Q4 revenue 8.37 bln riyals vs 8.64 bln riyals a yr ago
* 2013 full year profit 2.58 bln riyals vs 2.94 bln riyals in 2012 (Adds reason for the profit drop)
By Matt Smith
DUBAI, March 4 Qatari telecom operator Ooredoo posted a 36 percent drop in fourth-quarter net profit on Tuesday as foreign exchange losses and start-up costs ahead of its Myanmar launch weighed.
The former monopoly, which operates in countries across the Middle East, Africa and Asia, made a profit of 510 million rials ($140.05 million) in the three months to Dec. 31, down from 790.9 million riyals in the year-earlier period, it said in a statement.
Two analysts polled by Reuters forecast Ooredoo, which changed its name from Qatar Telecom in February 2013, would make a quarterly profit of between 547.2 million riyals and 841.5 million riyals.
Ooredoo's full-year net profit for 2013 was 2.58 billion riyals, down from a profit of 2.95 billion riyals a year earlier.
Its earnings before interest, tax, depreciation and amortisation (EBITDA), a key industry metric, was 14.6 billion riyals last year, down 6 percent on 2012.
Ooredoo's EBITDA margin dropped to 43 percent from 47 percent over the same period.
The company said its EBITDA declined because of falling revenue at its Indonesian unit Indosat, Myanmar start-up costs, rebranding expenses and investments in improving its network in Kuwait. Indonesia's rupiah fell 26 percent against the dollar in 2013.
Last June, Ooredoo won one of two mobile licences on sale in Myanmar.
Fourth-quarter revenue was 8.37 billion riyals. This compares with 8.64 billion riyals a year ago.
Annual revenue rose 1.1 percent to 33.9 billion riyals.
($1 = 3.6416 Qatar riyals) (Reporting by Matt Smith; Editing by Yara Bayoumy and Louise Heavens)