diff --git a/src/sudo.rs b/src/sudo.rs
index 81306c84..04cb85ec 100644
--- a/src/sudo.rs
+++ b/src/sudo.rs
@@ -252,7 +252,7 @@ impl Sudo {
             },
             SudoPreserveEnv::Some(vars) => match self.kind {
                 SudoKind::Sudo => {
-                    cmd.arg(format!("--preserve_env={}", vars.join(",")));
+                    cmd.arg(format!("--preserve-env={}", vars.join(",")));
                 }
                 SudoKind::Run0 => {
                     for env in vars {