UPDATE 1-Turk Telekom's net profit falls 27 pct

* Turk Telekom Q1 sales 2.5 billion lira

* Q1 net profit 291.1 million lira

* EBITDA 1.087 billion lira

ISTANBUL, April 20 (Reuters) - Fixed-line operator Turk Telekom (TTKOM.IS) on Monday posted a first-quarter net profit down 27 percent at 291 million lira ($177 million), below forecasts as its operating profit beat expectations.

Turk Telekom, which says it is Europe's No.5 fixed-line operator, said it was targeting between 8 percent and 10 percent consolidated revenue growth in 2009.

The company said that sales rose 3.5 percent to 2.5 billion lira and its operating profit, or earning before interest, taxes, depreciation and amortization (EBITDA), came in at 1.087 billion lira, a slight increase from last year's 1.080 billion lira.

The average estimate in a Reuters poll of 10 analysts was for net profit of 362 million Turkish lira and EBITDA at 1.06 billion lira on sales of 2.57 billion lira.

Analysts have noted that the company, which owns No.3 mobile phone operator Avea, has been hit by the weakness of the lira and costs as it fights for clients in Turkey's fiercely competitive mobile market.

Steep falls in the value of the lira have made the cost of servicing Turk Telekom's considerable foreign exchange-denominated debt more expensive, and marketing costs to lure new subscribers have hit profit margins, which slipped to 43 percent in the first three months of 2009 from 45 percent a year ago.

Even with a recovery in recent weeks, the Turkish lira has still lost 4.5 percent of its value to the dollar since the start of 2009.

The introduction last November of mobile-number portability -- allowing customers to keep their numbers when switching operators -- heightened competition in the Turkish market, which has some of the highest penetration rates in Europe.

Telecoms are commonly seen as defensive in a downturn as revenues remain reasonably resilient.

Of eight analysts that have rated the stock, five gave it a "buy" or an "outperform", one a "hold", and two an "underperform" or a "sell".

Turk Telecom shares closed down 3.4 percent at 3.96 lira before the results were announced. They have gained 17 percent on the year, outperforming Turkey's index of leading shares .XU100, which is up 9.77 percent. (Editing by Karen Foster)