A computer-assisted video extensometer was used to measure the Young's modulus and tensile strength of commercially available alumina fibres (11.5 mu m in diameter). The results showed excellent agreement with manufacturers reported values (384 +/-12 GPa and 3132 +/- 296 MPa for Young's modulus and tensile strength, respectively). The machine was initially tested with 100 mu m diameter SiC monofilaments to identify optimum experimental conditions. The mechanical properties of these fibres were independent of the crosshead speed and fibre length. This non-contacting extension measuring system allowed testing of fragile materials and a submicron resolution could be achieved with a high-precision CCD camera. The results in term of precision and resolution therefore meet the requirements for strain measurements in mechanical ceramic materials testing.