| Issue | #3 |
| Published | Winter 1940 |
| Cover Price | 0.10 USD |
| Pages | 68 |
| Editing | Victor Fox |
| Characters | The Green Mask [Michael Shelby]; Domino [Don] |
| Pencils | Chuck Cuidera? |
| Inks | Chuck Cuidera? |
| Characters | The Green Mask [Michael Shelby]; Radion [Pelson] (first appearance; villain) |
| Pencils | Walter Frehm? |
| Inks | Walter Frehm? |
| Characters | The Green Mask [Michael Shelby]; Marilyn Rich (first appearance; villain) |
| Pencils | Walter Frehm? |
| Inks | Walter Frehm? |
| Characters | The Green Mask [Michael Shelby]; The Brain (first appearance; villain) |
| Pencils | Walter Frehm? |
| Inks | Walter Frehm? |
| Script | Nathaniel Nitkin [as N. N. Nathaniel] |
| Letters | typeset |
| Pencils | Art Peddy |
| Inks | Art Peddy |
| Reprinted | from MYSTERY MEN COMICS #1 |
| Pencils | George Tuska |
| Inks | George Tuska |
| Reprinted | from WONDER COMICS #1 |
| Script | Will Eisner? |
| Pencils | Bob Powell |
| Inks | Bob Powell |
| Reprinted | from MYSTERY MEN COMICS #1 |
| Pencils | Art Peddy |
| Inks | Art Peddy |
| Reprinted | from MYSTERY MEN COMICS #4 |