diff --git a/src/needs-parens.mjs b/src/needs-parens.mjs
index 2bd051fc0..75fbc8cc5 100644
--- a/src/needs-parens.mjs
+++ b/src/needs-parens.mjs
@@ -29,6 +29,10 @@ function needsParens(path, options) {
   }
 
   switch (node.kind) {
+    case "intersectiontype":
+      // An intersection inside a union is a DNF type and must keep its
+      // parentheses: `(A&B)|C` is valid PHP, `A&B|C` is a parse error.
+      return parent.kind === "uniontype";
     case "pre":
     case "post":
       if (parent.kind === "unary") {
diff --git a/tests/dnf-types/__snapshots__/jsfmt.spec.mjs.snap b/tests/dnf-types/__snapshots__/jsfmt.spec.mjs.snap
new file mode 100644
index 000000000..2f19ac6fc
--- /dev/null
+++ b/tests/dnf-types/__snapshots__/jsfmt.spec.mjs.snap
@@ -0,0 +1,41 @@
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+
+exports[`dnf.php 1`] = `
+====================================options=====================================
+parsers: ["php"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+<?php
+function a((A&B)|C $x): void {}
+
+function b(): (A&B)|C {}
+
+function c(C|(A&B) $x): void {}
+
+function d((A&B)|(C&D) $x): void {}
+
+function e((A&B) $x): void {}
+
+$f = function ((A&B)|C $x): void {};
+
+$g = fn((A&B)|C $x) => $x;
+
+=====================================output=====================================
+<?php
+function a((A&B)|C $x): void {}
+
+function b(): (A&B)|C {}
+
+function c(C|(A&B) $x): void {}
+
+function d((A&B)|(C&D) $x): void {}
+
+function e(A&B $x): void {}
+
+$f = function ((A&B)|C $x): void {};
+
+$g = fn((A&B)|C $x) => $x;
+
+================================================================================
+`;
diff --git a/tests/dnf-types/dnf.php b/tests/dnf-types/dnf.php
new file mode 100644
index 000000000..c68cdcce9
--- /dev/null
+++ b/tests/dnf-types/dnf.php
@@ -0,0 +1,14 @@
+<?php
+function a((A&B)|C $x): void {}
+
+function b(): (A&B)|C {}
+
+function c(C|(A&B) $x): void {}
+
+function d((A&B)|(C&D) $x): void {}
+
+function e((A&B) $x): void {}
+
+$f = function ((A&B)|C $x): void {};
+
+$g = fn((A&B)|C $x) => $x;
diff --git a/tests/dnf-types/jsfmt.spec.mjs b/tests/dnf-types/jsfmt.spec.mjs
new file mode 100644
index 000000000..8829c872f
--- /dev/null
+++ b/tests/dnf-types/jsfmt.spec.mjs
@@ -0,0 +1 @@
+run_spec(import.meta, ["php"]);