This data set includes geocryological data from boreholes in the in the Yamburg and Medvezhje gas fields of western Siberia, Russia. Parameters include ground temperature, active layer depth, ground ice, and soil properties, and the data set includes computer modelling. Ground temperature was measured every 1.0 m to adepth of 15 m. Data were collected during 1972-74, 1976, 1984-87, and 1994-2000. Results are presented in tabular form and as engineering-geocryological maps and profiles (scale 1:500 to 1:1000). Data are stored at the National Geocryological Fund, Moscow, under the following Archive Numbers - 16584; 16584, 16664; 15992; 13957; 15727; 15558; 15557; 15805, 15805a; 15745; 12267, 11534, 11601; 11535, 11563; 11536, 12646; 15791, 15792; 11236; 11303; 11631(8824); 11813; 11843(9037); 13198(11094); 13282(9801); 13951; 15518; 15558; 15791; 15792; 15992; 16096; 21071; 19830; 19894; 20018; 20026; 20208; 20304; 20986; 21018; and 21317. This data set is at risk of being lost.