Young man gives up his dream of becoming an astronaut to go into business — and finds himself turned into a little old man.
| Actor | Role |
|---|---|
 Jonathan SilvermanSeymour | Seymour |
 Robert ProskyGrandpa Irving | Grandpa Irving |
 Rita MorenoRita | Rita |
| RRita KarinFlo | Flo |
 Robert CicchiniBruno | Bruno |
| BBrian WilliamsGerrard | Gerrard |
 Paul SorvinoMax | Max |
 MacIntyre DixonMortini | Mortini |
 Alvin EpsteinDr. Hirsch | Dr. Hirsch |
 Dee HotyDr. Ripper | Dr. Ripper |
 Sylvia KaudersOld Woman | Old Woman |
| LLarry KeithDr. Morton | Dr. Morton |
 Michael MantellDr. Chase | Dr. Chase |
 Michael P. MoranForeman | Foreman |
| MMarilyn PasekoffDr. Sandy Franklin | Dr. Sandy Franklin |
 Stephen PearlmanNot listed | Not listed |
| JJoyce ReehlingMrs. Delfino | Mrs. Delfino |
 Sharon SharthDr. Barker | Dr. Barker |
 Brian SmiarDr. Bush | Dr. Bush |
 Shirley StolerMadam Iris | Madam Iris |
| RRalph WilliamsNot listed | Not listed |
| HHoward WittRifkin | Rifkin |
 Bella AbzugSelf | Self |
 Joyce BrothersSelf | Self |
| KKreskinSelf | Self |
| LLloyd Lindsay YoungSelf | Self |
| BBen EllerinYoung Seymour (uncredited) | Young Seymour (uncredited) |