In the modern era the research, assessment and effective use of underground waters are the pri-ority issues in solving the water problems. Among natural factors the geological-structural, geomorpho-logical, hydrological and climatic factors play an exceptional role in the underground waters formation. Moreover the artificial factors influence is also one of the main factors in the underground waters for-mation. The article has been devoted to the research of the natural and artificial factors role in the un-derground waters formation of the Terterchay alluvial fan entering in the Karabakh piedmont plain. With-in the Karabakh massif underground waters at 300-400 m depth are represented by 1 underground and 5 confined water-bearing horizons (aquifers). They have a common recharge zone and are hydraulically interconnected.