Dr. Caldwell (Davis Roberts) is the Sanford's entertaining family doctor who shows up in several early episodes. He often enters the Sanford residence with an alarming cough, and his credentials as a doctor are highly questionable. Asked if he is really a doctor he claims "On Monday, Wednesday and Friday, I'm a doctor. The other days I work in the post office". His other reply to being asked if he really is a doctor is that it depends on who's asking. If you're asking him, he says he is a doctor, but when asked who says he's not a doctor, his reply is "the state of California." He has also replied that he's a doctor "in some states." His diagnoses are based upon little to no examination and has also claimed to specialize in whiplash. He usually doesn't know the answers to any of the questions proposed to him and also agrees with opposing statements. He asks Fred "Do you know how many doctors are afraid to say 'I don't know'", to which the doctor replies "I don't know." He calls his practice "Caldwell & Caldwell" simply because the phone is in his father's name.