The Recombination Index of Radiation Quality, Q4, is a measurable quantity which may, serve as approximation of the radiation quality factor. Values of Q4 measured in fields of monoenergetic neutrons are presented and compared with the calculated values of the effective quality factor in ICRU sphere. The Q4 index can be also used for determination of the quality factor according to the ICRP Report 60. The procedure for calculation of the ''new'' quality factor is described and illustrated by experimental results obtained for monoenergetic neutrons in the energy range from 75 keV to 19 MeV.