Preheat oven to 350°F.
Drain the mandarin oranges, making sure to reserve the syrup for later use.
Grease and flour two loaf pans or line them with parchment paper.
In a large mixing bowl, cream together the butter and sugar until light and fluffy.
Add eggs one at a time, mixing will after each egg.
Add the pumpkin puree and 2/3 cup of the reserved mandarin orange syrup, mix until well combined.
In a separate bowl, sift together the, flour, baking soda, baking powder, salt, cinnamon, and nutmeg.
Gradually add the dry ingredients into the wet mixture, stirring until just combined.
Gently fold the mandarin oranges into the batter, breaking up the oranges slightly to distribute around the loaf.
Pour batter evenly into the prepared loaf pans.
Bake for 60 minutes, or until a toothpick comes out clean.
Cool for 15 minutes, then enjoy!