The authors offer a picture of the paleogeographical development of the basin, the torso of which is found in the area of the Myjavska pahorkatina Upland. The basin originated in the Upper Cretaceous (Coniacian) in the furrow between the Klippen Belt and the Brezovske and Cachticke Karpaty Mts. At present its width is reduced at least 5 times. It is possible to distinguish an earlier Danian — (Montian) and a later Thanetian succession from the Paleocene. During the Danian — (Montian), a reef complex arose and developed at the edge of the basin. During the Thanetian, progradation, shifting of the reef sedimentation to the interior of the basin, and emergence and karstification of the Danian — (Montian) reef limestones occurred. Lagoonal, back-reef, reef and fore-reef (seaward slope) facies can be distinguished in the reef complex. Remnants of the rocks of the reef complex in the Male Karpaty Mts., the Vah Valley and northern Orava, show that the basin, with a minimum width of 40 km, had a length exceeding 200 km, and it was, in our opinion, connected with a similar basin in the Northern Calcareous Alps. The Myjava Basin has certain distinguishing features compared to the basin in which the Paleocene reef complex of the Middle Vah Valley and the Pieniny Mts. (assigned to the Manin Unit s.l.) developed.