Recently the European Commission started a project in order to harmonize the gas quality in the European Union. In 2007, a mandate was published to the European Committee for Standardization for drawing up standards for gas quality parameters for group H-gas. This mandate was in close relation with the Directive 2003/55/ EC of the European Parliament. This article presents the results of a survey for the quality of the natural gas, which is distributed in Greece. Random samples were tested for 20 days and the main parameters were recorded and examined. The results indicate a significant fluctuation in the examined gas characteristics.