The article considers the peculiarities of intergovernmental fiscal relations between the central budget level and the subcentral (regional / local or local only) budget levels in federative and unitary states on the basis of the Organisation of Economic Cooperation and Development’s statistics (OECD statistics). The author analysed several quantitative indicators characterizing the subcentral budget levels’ positions in the following lines: tax autonomy, intergovernmental grants, revenue and spending of the consolidated budget, tax revenue and intergovernmental transfer revenue, budget balance and budget debt, fiscal rules and financial stability. Some significant differences were identified between the groups of federative and unitary states; also in several cases some serious deviations from the intragroup average values were discovered. According to the author’s own calculations, the OECD countries were allocated into four categories based on the value of the integral indicator characterizing the role of subcentral budget levels. It helped to conclude that there is quite a close link between the federative / unitary type of the state and the degree of budget decentralisation and at the same time the decentralized systems of intergovernmental fiscal relations can be found not only in the federative, but also in the unitary states.