Toss the pumpkin seeds in the olive oil so they are evenly coated.
Spread the seeds out on a tray, and roast in the preheated oven. Check after 10 minutes, the seeds are ready when they are starting to turn golden brown. If you need to roast them for longer, keep an eye on them, as they will burn easily.
Leave the seeds to cool and store in an airtight container.