The Mezen sedimentary basin (frequently called the Mezen syneclise) situated on the northeastern Russian Platform has an area of aprroximately 300 000 km². The volume of its sedimentary filling exceeds 10⁶ km³. Riphean and Vendian sediments accounting for 75 vol % of this sequence. The study of the basin and exploration of oil land gas deposits has been undertaken intermittently. Stages of intense study (the last one continuing now) have alternated with periods of calm when exploration work was stopped almost completely. In addition to geophysical work of varying quality and scale, sixteen deep wells have been drilled in the Mezen Basin to date. However, none of them have revealed reliable oil and gas manifestations. This work yielded basically new results that completely change our conceptions of the distribution of inferred hydrocarbon pools and, thus, on exploration for them in the Mezen Basin. In this communication, we first briefly present these data and relevant inferences on the most promising objects. It should be emphasized that no one can as of yet guarantee the discovery of commercial deposits in the Mezen Basin, but we believe that the probability of such a discovery now exceeds 50%.