The paper presents the results of research on one area of the Early Medieval fortified settlement called Hradisko I in Spisske Tomasovce. The trapezoid-shaped area of approx. 3 ha. is from three sides fortified by a rampart of a timber chamber construction with outer stone wall. On the fourth eastern side the ramparts were joined to a rocky hillside of a possible acropolis of the fortified settlement Hradisko. The technical parameters of the fortification were not unified; the northern mound was 3.9-4 m wide, the western one did not reach 3.2 m. Dimensions of the chambers, which were indicated by the strips of burnt subsoil and remains of woods, ranged between 1.5-2 m x 1.9-2.3 m. The analyzed samples of woods proved mostly spruce and pine. The timber base grates and a vertical timbering of inner rampart wall were found at the northern mound. Considering the rampart strategy and static, the sorest points - the north-western corner, the gate in this corner and that in the western part of the northern mound - were reinforced with a special construction. The draining system of the surface waters was revealed, too. In front of the northern rampart a ditch up to 2 m deep and 7.5-8 m wide was found. The other ditch outside the northern rampart, with its dimensions alike the former one, and destruction of a stone-earthen mound indicate existence of the another smaller fortified area (of approx. 35 x 80 m). The type of the ramparts enclosing the main area represents a principal fortification technology in Slavic mid-Danubian (Great Moravian) defense construction in the 9th-10th centuries. Almost thirty fortified settlements that were built by analogical technology have been known from the regions of Slovakia, Moravia, Austria and Czech republic, another were explored between the Elbe and the Saale rivers, in Silesia and the Little Poland. Usually they are connected with the east-Frankish influence on local defense architecture, secondarily they are considered to be the influences of the Great Moravia or later Czech state. Considering the construction static, technology and the used materials, assumed height of the western rampart together with a palisade breast is approx. 2.6-3.6 m and of the northern rampart 3.6-4.1 m. Briefly calculated amounts of the construction material needed for 520 m long unequally thick mound of the main area on the terrace are: about 270 cubic m of timber for the chambers, about 60 cubic m of timber for the palisades, 1000 cubic m stone for the screens and 2250 cubic m of earth for the chamber fillings, what is together 3600 cubic m of the construction material, i. e. almost 7 cubic m of the construction material for a standard meter. Based on its superpositions, the fortification is dated to the terminal 8th up to the middle 9th centuries.