Recombination in a helium and helium-hydrogen plasma wasexperimentally investigated in the linear divertor simulatorNAGDIS-II. To identify the physical mechanisms, electron-ionrecombination (EIR) and molecular assisted recombination (MAR), theplasma parameters in the recombining region have been measured. Weused spectroscopic techniques on the basis of continuum emission andline emission from highly excited levels due to EIR and Langmuir probes. The dependence of the plasmaparameters on the neutral pressure in a pure helium plasma and in ahelium-hydrogen mixture shows clearly that recombination is caused bydifferent processes in the two cases. In a pure helium plasma aroll-over and a following decrease of the electron density as well asa monotonic decrease of the electron temperature down to 0.1 eV wereobserved when increasing the helium pressure. Here EIR is therecombination mechanism. Conversely, when hydrogen is added to thehelium plasma, the electron density decreases monotonically while thecentral electron temperature remains above 1 eV. This particularbehaviour in the helium-hydrogen plasma can only be explained by thedominant action of MAR.