(1) The vibration method of indirect tensionmeasurement for any existing skyline logging cable is proved by the authors' experiments to be very convenient and considerablly accurate. (2) The values of cable tension measured by the propagating velocity of the vibration waves may be utilized for practical purposes in many cases. (3) Probable maximum tension, Tmax, of a skyline cable, on which a single concentrated load is applied, is given by the formula, Tmax=γ·T where, T denotes the value of tension of the same cable measured by vibration method when no load is applied on it. Coefficient γ is theoretically caIcurated by eqs. (3), (4), (5), according to form and weight of cable and amount of löad applied on it. (4) Tabulated numerical values of coefficient γ may be very useful for practical procedures.