Low temperature plasma systems used for fluid treatment G.Popa and Alina Chiper “Al.I.Cuza” University, Faculty of Physics, Brd. Carol I, &00506, Iasi, Romania Nowadays a special interest is paid for studying and developing the plasma system able to treat or to process fluids as gasses, liquids or mixture of them. The purposes are multiple and they refer to different scientific and applied problems. Thus, new material synthesis used in electronic industry or medicine and related field are produced from gas phase using primarily low temperature plasma. Coating protection and surface treatment of different materials used in manufacturing of the tools or utilities are also performed in a plasma system produced in gas mixtures or in combination of gases and vapors of the chemical precursor used in liquid phase. Environmental issue is also of great interest taking into account that industrialization is leading to a dramatic pollution of the both air and water. Thus, treatment of industrial wastes starting first with exhausting gases of the cars and planes and ending with tail water is one of the crucial problem of the mankind facing the global warming and shortage of the sources for drinking water. In the lecture principles are presented of the plasma systems used in treatment of the gases, liquids or of the surfaces of the solid materials. Descriptions of some technical and laboratory devices are also presented with their qualities and problems, which still remain to be solved.