The Yamal peninsula is located in the northern portion of the West Siberia basin adjacent to the Kara Sea. The sedimentary succession is composed of between 2.5 and 9 km of Jurassic through Paleogene sediment, deposited within lacustrine through deep marine settings. Although the region is remote and hydrocarbon exploration has been limited, a number of discoveries have been made. Components of the region's petroleum system are, however, poorly known. This study examines aspects of hydrocarbon charge through the integration of new data obtained on core samples from the Malygin field and from 10 oils from five fields (Bovanenkov, Malygin, Kharasavey, Pyaseclaysk, and New Port) with published data. Source rock screening data from the Malygin field reveal the presence of organic-rich intervals (TOCs approaching 6%) within the Cretaceous and Jurassic sequences. These data also indicate that at the sampling location these intervals are gas-prone (hydrogen index values less than 300 mg HC/g TOC). Within the Cretaceous interval, the gas-prone character appears to be largely depositional. In contrast, in the Jurassic portion of the sequence the hydrogen indices appear to have been reduced as a result of an advanced level of thermal maturity. Elsewhere on the peninsula where the thermal maturity of the Jurassic is less advanced, data suggest that the Jurassic sequence includes oil-prone intervals. Preliminary review of the oil data suggests that the examined oils belong to a single family (i.e., were derived from a common source) and that much of the variation is a result of different alteration and migration histories. Although the data from this study were incapable of establishing a definitive correlation, published information and the lack of an effective Cretaceous liquid hydrocarbon source suggests that these oils were derived from the Jurassic sequence. (C) 2003 Elsevier Science B.V. All rights reserved.