During last 50 years of exploration more than 120 gas and oil fields were discovered in the Carpathian Foredeep. The bulk of produced hydrocarbons (97%, mainly gas), were contained in the Miocene deposits, with a further 3% in the Miocene basement. The Miocene contains only gas, while both oil and gas were found in the basement rocks. The Miocene gas reservoirs are typically multi-horizon and saturated by the gas of very high methane content, usually 95 - 99%. About 90 billion cubic meters of this kind of gas were already produced. The Przemyoel Gas Fields Group is the largest one in Poland with GIIP of the near 71 billion cubic meters and the cumulative field production, as of December 31, 2002, amounted to 55 billion cubic meters. Better prospecting methods, particularly the direct hydrocarbons indicators (DHI) methods, opened a new stage of the exploration of gas accumulations in the Miocene deposits. Only during last 8 years near 20 new gas fields were discovered with these methods. The history and the physical background of the DHI methods were presented.