 Walter PidgeonNicholas 'Nick' Carter, aka Robert Chalmers | Nicholas 'Nick' Carter, aka Robert Chalmers |
 Rita JohnsonLou Farnsby | Lou Farnsby |
 Henry HullJohn A. Keller | John A. Keller |
 Stanley RidgesDoctor Frankton (as Stanley C. Ridges) | Doctor Frankton (as Stanley C. Ridges) |
 Donald MeekBartholomew, the bee man | Bartholomew, the bee man |
 Addison RichardsStreeter - President of Radex | Streeter - President of Radex |
 Henry VictorHammil - tall spy boss | Hammil - tall spy boss |
 Milburn StoneKrebs - 2d hurt worker | Krebs - 2d hurt worker |
 Martin KosleckOtto - 3d hurt worker | Otto - 3d hurt worker |
 Frank FaylenPete Foley - 1st pilot | Pete Foley - 1st pilot |
 Sterling HollowayBartholomew's Bee Asst. | Bartholomew's Bee Asst. |
| WWally MaherCliff Parsons - Keller's Pilot & Asst. | Cliff Parsons - Keller's Pilot & Asst. |
 Edgar DearingHarbor Patrol Sgt. Denny | Harbor Patrol Sgt. Denny |
| EErnie AlexanderFactory Workman | Factory Workman |
| LLouis V. ArcoYacht Captain | Yacht Captain |
 Frank BallPeake the Gardener | Peake the Gardener |
 Don BrodieEngel - X-49 Workman | Engel - X-49 Workman |
 Don CastleEd - 1st Hurt Worker | Ed - 1st Hurt Worker |
 Eddy ChandlerJoe - Blueprint Security Officer | Joe - Blueprint Security Officer |
 Gene CooganWelder | Welder |
 Paul EllisFaber - Henchman | Faber - Henchman |
 Bud GearySeaman on Yacht | Seaman on Yacht |
 Chuck HamiltonEntrance Guard | Entrance Guard |
 Edward HearnDeputy | Deputy |
 Kenner G. KempStudent | Student |
| WWilliam LallyExit Guard | Exit Guard |
 Richard LaneSam Vaughn | Sam Vaughn |
 Carey LoftinMinor Role | Minor Role |
 Wilfred LucasPolice Detective Randall | Police Detective Randall |
| JJoseph P. MackDraughtsman | Draughtsman |
