Stable isotopes of oxygen (δ¹⁸O), deuterium (δ²H) and deuterium excess (dexc) in massive ice at the third terrace of the Seyaha River, and ice wedge, cryopeg samples and water of river and lake in the Bovanenkovo Gas field area.Isotope analyses were done in the isotope laboratory of the Austrian Research Center (ARC), in Seibersdorf (Dr. W. Papesch). Stable isotope measurements were performed using isotope mass spectrometers (Finnigan MAT 251 and Delta Plus XL), equipped with automatic equilibration lines. All results were reported as relative abundance (δ²H and δ¹⁸O, respectively) of the isotopes ²H and ¹⁸O in permil (‰), with respect to the international standard VSMOW (Vienna Standard Mean Ocean Water). The accuracy of δ²H and δ¹⁸O measurements is better than ± 1, 0‰ and ±0,1‰, respectively.