A pressure-measuring guidewire system includes a hollow guidewire (110) in sealed interconnection with a contained volume (102) of a connector (101). The contained volume is bordered on at least one side by a septum (103). A pressure sensor unit (122) includes a transducer (130) associated with a hollow needle (131) which can be inserted to penetrate the septum (103), thereby connecting the transducer with a column of fluid within an inner lumen of the guidewire (102). Priming of the guidewire is performed prior to use, typically by use of a syringe, prior to connection of the sensor unit, thereby protecting the transducer from damage from the priming pressure. Also disclosed is a guidewire tip configuration which provides effective fluid connection for pressure measurement while maintaining the properties of a conventional guidewire.