How companies file corporate income tax returns

The tax period for corporate income tax coincides with the tax year, and the annual corporate income tax return is due and payable after the end of the tax period, by the 15^th day of the sixth month of the following tax period (or by 15 June, if the tax period coincides with the calendar year). To file their annual corporate income tax returns, private limited liability companies and small partnerships must submit Form PLN204; sole proprietorships, general partnerships and limited partnerships must submit Form PLN204A; non-profit organizations must submit Form PLN204N. For more detailed information, please see here (only in Lithuanian). 

If taxable income for the previous tax period exceeds EUR 300,000, then companies must pay advance corporate income tax. At the beginning of each year, companies may choose the method of calculating the advance corporate income tax, either on the basis of previous year results, or on the basis of the estimated corporate income tax amount for the tax period. The due date for submitting Advance Corporate Income Tax Return Form FR0430 depends on the method chosen for calculating the advance corporate income tax.
For more information on when no advance corporate income tax is due, please see here (only in Lithuanian).