In 2006, the Physikalisch-Technische Bundesanstalt (PTB), Germany submitted a sample of known activity of Re to the International Reference System (SIR). The value of the activity submitted was about 166 MBq. This comparison result is the first submission in the ongoing key comparison BIPM.RI(II)-K1.Re-186. The result agrees with that predicted from the efficiency curve for the SIR within a standard uncertainty.