Radiophobia - Fear of radiation or x-rays.
Ranidaphobia - Fear of frogs. (Batrachophobia)
Rectophobia - Fear of rectums, rectal pain or rectal diseases. (Proctophobia)
Rhabdophobia or Rhobdophobia - Fear of being criticized or punished or fear of being beaten by a rod or fear of magic (wands).
Rhypophobia or Rupophobia or Rypophobia - Fear of dirt, filth, defecation or being soiled.
Rhytiphobia - Fear of getting wrinkles.
Russophobia - Fear of Russia or Russian culture.