tGovernment accounting (GA) and National accounts (NA) are two reporting systems that, although aimingdifferent purposes, are linked – public administrations’ financial information for the latter is provided bythe former. Therefore, the alignment between the two systems is an issue for the reliability of the publicsector aggregates finally obtained by the National Accounts.In the EU context, this is a critical issue, inasmuch as these aggregates are the reference for monitoringthe fiscal policy underlying the Euro currency. However, while reporting in NA is accrual-based andharmonised under the European System of Regional and National Accounts, the GA each country still hasits own reporting system, often mixing cash basis in budgetary reporting with accrual basis in financialreporting, hence requiring accounting basis adjustments when translating data from GA into NA.Starting by conceptually analysing the accounting basis differences between GA and NA and the adjust-ments to be made when translating data from the former into the latter, this paper uses evidence fromthree southern European countries – Portugal, Spain and Italy, representing the southern ContinentalEuropean accounting perspective, with cash-based budgetary reporting, and where budgetary deficitshave been particularly significant in the latest years – to show how diversity and materiality of theseadjustments may question the reliability of the budgetary deficits finally reported in NA.The main findings point to the need for standardised procedures to convert cash-based (GA) intoaccrual-based (NA) data as a crucial step, preventing accounting manipulation, thus increasing reliabilityof informative outputs for both micro and macro purposes.