Nielsen data suggests "Marcus Welby, M.D." was tuned in on TV sets in one of every four American homes in 1970.

  1. Marcus Welby, M.D. (ABC)
  2. The Flip Wilson Show (NBC)
  3. Here's Lucy (CBS)
  4. Ironside (NBC)
  5. Gunsmoke (CBS)
  6. Hawaii Five-O (CBS)
  7. Medical Center (CBS)
  8. Bonanza (NBC)
  9. The F.B.I. (ABC)
  10. The Mod Squad (ABC)