diff --git a/changelog/4592.bugfix.rst b/changelog/4592.bugfix.rst
new file mode 100644
index 00000000000..f1eaae7eb01
--- /dev/null
+++ b/changelog/4592.bugfix.rst
@@ -0,0 +1 @@
+Fix handling of ``collect_ignore`` via parent ``conftest.py``.
diff --git a/src/_pytest/main.py b/src/_pytest/main.py
index d0d826bb653..68d5bac40d1 100644
--- a/src/_pytest/main.py
+++ b/src/_pytest/main.py
@@ -607,6 +607,7 @@ def filter_(f):
                 yield y
 
     def _collectfile(self, path, handle_dupes=True):
+        assert path.isfile()
         ihook = self.gethookproxy(path)
         if not self.isinitpath(path):
             if ihook.pytest_ignore_collect(path=path, config=self.config):
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index aaa49f7dd87..48962d137d0 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -599,6 +599,7 @@ def gethookproxy(self, fspath):
         return proxy
 
     def _collectfile(self, path, handle_dupes=True):
+        assert path.isfile()
         ihook = self.gethookproxy(path)
         if not self.isinitpath(path):
             if ihook.pytest_ignore_collect(path=path, config=self.config):
@@ -642,11 +643,12 @@ def collect(self):
             ):
                 continue
 
-            if path.isdir() and path.join("__init__.py").check(file=1):
-                pkg_prefixes.add(path)
-
-            for x in self._collectfile(path):
-                yield x
+            if path.isdir():
+                if path.join("__init__.py").check(file=1):
+                    pkg_prefixes.add(path)
+            else:
+                for x in self._collectfile(path):
+                    yield x
 
 
 def _get_xunit_setup_teardown(holder, attr_name, param_obj=None):
diff --git a/testing/test_collection.py b/testing/test_collection.py
index 36e8a69ce8a..329182b0f1e 100644
--- a/testing/test_collection.py
+++ b/testing/test_collection.py
@@ -1144,3 +1144,16 @@ def test_nodeid(request):
         ]
     )
     assert result.ret == 0
+
+
+def test_collectignore_via_conftest(testdir, monkeypatch):
+    """collect_ignore in parent conftest skips importing child (issue #4592)."""
+    tests = testdir.mkpydir("tests")
+    tests.ensure("conftest.py").write("collect_ignore = ['ignore_me']")
+
+    ignore_me = tests.mkdir("ignore_me")
+    ignore_me.ensure("__init__.py")
+    ignore_me.ensure("conftest.py").write("assert 0, 'should_not_be_called'")
+
+    result = testdir.runpytest()
+    assert result.ret == EXIT_NOTESTSCOLLECTED