The Siberian fixed-line service provider's earnings (net of subsidiaries) hit 23.08 billion rubles (about $887.8 million) in the reporting period, 5.4% more than in the same period in 2005, the company said in a statement.
The company attributed the increase in its income to an expanded client base and Internet traffic, the development of its mobile phone business, and also to changes in its relations with other operators.
SibirTelecom is Russia's third-largest fixed-line telecoms operator by installed capacity, with 3.4 million active lines, and in terms of revenue. It is a subsidiary of Russia's state telecoms giant Svyazinvest.
The company's area of operations covers about 29% of the country's territory, and 14% of its population.