diff --git a/src/uu/mktemp/src/mktemp.rs b/src/uu/mktemp/src/mktemp.rs
index 4a77da4c4..6a3f6f21b 100644
--- a/src/uu/mktemp/src/mktemp.rs
+++ b/src/uu/mktemp/src/mktemp.rs
@@ -281,7 +281,7 @@ impl Params {
             .join(prefix_from_template)
             .display()
             .to_string();
-        if options.treat_as_template && prefix.contains(MAIN_SEPARATOR) {
+        if options.treat_as_template && prefix_from_template.contains(MAIN_SEPARATOR) {
             return Err(MkTempError::PrefixContainsDirSeparator(options.template));
         }
         if tmpdir.is_some() && Path::new(prefix_from_template).is_absolute() {
diff --git a/tests/by-util/test_mktemp.rs b/tests/by-util/test_mktemp.rs
index f99f92a80..907f8cf1d 100644
--- a/tests/by-util/test_mktemp.rs
+++ b/tests/by-util/test_mktemp.rs
@@ -23,6 +23,7 @@ static TEST_TEMPLATE7: &str = "XXXtemplate"; // spell-checker:disable-line
 static TEST_TEMPLATE8: &str = "tempXXXl/ate";
 #[cfg(windows)]
 static TEST_TEMPLATE8: &str = "tempXXXl\\ate";
+static TEST_TEMPLATE9: &str = "a.XXXX";
 
 #[cfg(not(windows))]
 const TMPDIR: &str = "TMPDIR";
@@ -569,6 +570,34 @@ fn test_template_path_separator() {
         ));
 }
 
+/// Test that a prefix with a point is valid.
+#[test]
+fn test_prefix_template_separator() {
+    new_ucmd!()
+        .args(&["-p", ".", "-t", TEST_TEMPLATE9])
+        .succeeds();
+}
+
+#[test]
+fn test_prefix_template_with_path_separator() {
+    #[cfg(not(windows))]
+    new_ucmd!()
+        .args(&["-t", "a/XXX"])
+        .fails()
+        .stderr_only(format!(
+            "mktemp: invalid template, {}, contains directory separator\n",
+            "a/XXX".quote()
+        ));
+    #[cfg(windows)]
+    new_ucmd!()
+        .args(&["-t", r"a\XXX"])
+        .fails()
+        .stderr_only(format!(
+            "mktemp: invalid template, {}, contains directory separator\n",
+            r"a\XXX".quote()
+        ));
+}
+
 /// Test that a suffix with a path separator is invalid.
 #[test]
 fn test_suffix_path_separator() {