Agricultural activity in Poland, just like business activity, is covered by VAT scheme. In agriculture it is permissible to settle VAT under general principles or as flat-rate. Settlement of VAT under general principles is voluntary, except for farmers keeping account books. From the subject literature it follows, however, that increasingly more often farmers choose the status of an active VAT payer; such trend was also observed among Polish FADN farms. The paper analyses the results of VAT settlement under general principles at farms forming a panel in 2010-2013, grouped according to economic size. Regardless of the economic size class, in each group the average VAT balance always showed a negative value, which meant refund of overpaid VAT to the farm. The VAT amount to be refunded was considerably increased by the VAT output, included in investment purchases. It can be assumed that investments were the main stimuli to resign from the status of flat-rate farmer. The amount of refunded VAT for farmers – active VAT payers, is not a component of family farm income (FFI), just like in the case of other taxpayers. It is a separate value, undoubtedly generating monetary income of a farmer, which over the four years in the researched farms constituted a huge support for them. A cut on investments and better effects of farming can result in reversal of the VAT settlement effect to the advantage of the Tax Office. Then a farmer can return to the flat-rate status, but one of the conditions of leaving the VAT scheme is the necessity to adjust the deducted VAT, which may not be favourable for the farmer.