Samsung says it is on track to post its second straight quarter of lower profit.
It estimates operating profit in the first three months of the year was 8.4 trillion won (5.8 billion euros, $7.96 billion) – a 4.3 percent fall.
The South Korean company is under growing pressure from cheaper Chinese rivals in the key smartphone market.
It is counting on the fifth version of its flagship Galaxy S smartphone, which goes on sale globally this week, to reverse the profit decline, but has had to price that handset about 10 percent cheaper than its predecessor and has cut back on marketing to save money.
Analysts said Samsung’s efforts to rein in component costs and make products that appeal to a wider audience will be crucial as it braces for what could be its first annual profit decline in three years.