Abstract: A method for testing the stability of installed wooden utility poles in a non-destructive manner, in particular to determine decay caused by fungal growth or insect infestation. A quantity E' that is proportional to the modulus of elasticity E of the utility pole is measured above ground level at at least two different heights which are spaced apart by at least one meter, one height being directly at ground level, by shooting a pin with a defined energy at the utility pole and measuring its deflection when it springs back. The conditions of stability are fulfilled when the quantities E' measured at different heights deviate from one another by less than 30%. The invention enables one to objectively assess the condition of utility poles as well as to quantitatively characterize this condition.