diff --git a/content/projects/noxos/docs/sysabi.md b/content/projects/noxos/docs/sysabi.md
index 7e3fee1..d785091 100644
--- a/content/projects/noxos/docs/sysabi.md
+++ b/content/projects/noxos/docs/sysabi.md
@@ -14,7 +14,7 @@ To perform a syscall, you need to populate the following registers:
 | rax      | The syscalls ID |
 | rdi      | Argument 1      |
 | rsi      | Argument 2      |
-| rbx      | Argument 3      |
+| rdx      | Argument 3      |
 | rcx      | Argument 4      |
 
 The following calls should be included to some degree in NoxOS 1.0.