Inthispaperwedescribeatechniqueforspecifyingtimerelatedprop- erties on traditional software components. We apply the separation of concerns paradigm to allow independent specification of timing and to integrate time- checking specialized tool support into conventional software design processes. We aim at helping the designer to specify time contracts and at simplifying the introduction of time properties in the component behaviour description. We pro- pose to handle timing issues in a separate and specific design activity, in order to provide means of formal computation of time properties for component assem- blies without modifying in depth existing design processes.