In 2008 one ILC, for the calibration of extensometers (ER), was organ-ised in Italy by SIT-Italian Calibration Service. One of the difficulties for this kind of ILC is that the object of the comparison (the extensometer) has not the status of a reference standard.. In the ILC participated 8 SIT Centres. Each laboratory was asked to calibrate the ER by using its own procedure (normally UNI EN ISO 9513 and ASTM E83). In the present paper the main results obtained during the ILC are discussed, in particular the differences on the repeatability and accuracy given by the different laboratories are compared and evaluated. The results obtained by all the different laboratories were compatible among them as regards the repeatability, the accuracy (usually well inside Class 1 as required by the ISO Standard or B-2 by ASTM standard) and the En number as well.