• Ulula
    • Surnia ulula Missing - Chybi [Kupon 855] [Coupon 855]
  • Uncia
    • Panthera uncia Missing - Chybi [Známka 894] [Stamp 894]
  • Undulatus
    • Melopsittacus undulatus Missing - Chybi [Známka 409] [Stamp 409]
  • Ungulatus
  • Unicum
    • Dendrobium unicum Missing - Chybi [Kupon 730] [Coupon 730]
  • Unio
    • Unio Missing - Chybi pictorum [Aršik 563] [Souvenir Sheet 563]
  • Universitas
    • Universitas Missing - Chybi Comeniana Bratislavensis condita MCMXIX [Známka 817] [Stamp 817]
  • Upupa
    • Upupa Missing - Chybi epops L. [Známka 210] [Stamp 210]
    • Upupa Missing - Chybi epops [Známka 648] [Stamp 648]
  • Uralensis
  • Urbium
    • Praga mater urbium Missing - Chybi [Známka 1586] [Stamp 1586]
  • Urogallus
  • Ursus
    • Ursus Missing - Chybi arctos [Známka 955] [Stamp 955]
    • Ursus Missing - Chybi archtos [Známka 1572] [Stamp 1572]
    • Ursus Missing - Chybi arctos [Známka 816] [Stamp 816]