This document specifies a test method for determining the interfacial shear strength between a single fibre and a matrix by means of a pull-out test. The method can be used to measure the critical energy release rate. The method is applicable to reinforcement fibres such as carbon fibres, glass fibres, basalt fibres and similar stiff reinforcement fibres and to thermoset, thermoplastic and fine-grained concrete matrices. It can be used for polymeric reinforcement fibres and for other inorganic matrices. It is not applicable to: 1) elastomeric fibres and elastomeric matrices such as rubber; 2) matrices which cure or melt at temperatures above 400 °C; 3) matrices that show a strong tendency to bubble formation or expansion during the sample-preparation process; 4) foams.