diff --git a/changelog.rst b/changelog.rst
index 6e4c47c36..9eaeb99e6 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -3,6 +3,12 @@ Upcoming (TBD)
 
 Bug fixes:
 ----------
+* Fix ``-l``/``--list`` and ``--ping`` discarding the connection string. The
+  positional argument was unconditionally replaced with ``postgres``, which
+  also threw away a connection URI or ``key=value`` conninfo (host, user, port,
+  ``sslmode``, everything) and silently fell back to a local socket connection
+  as the OS user. Only a plain database name is discarded now; a connection
+  string that names no database gets ``postgres`` for the listing.
 * Restore cursor shape behaviour for Emacs mode
 * Fix ``TypeError: cannot use a string pattern on a bytes-like object`` when
   completion metadata comes back as bytes (e.g. ``SQL_ASCII`` client encoding).
diff --git a/pgcli/main.py b/pgcli/main.py
index e3ba5bfa8..d93813e69 100644
--- a/pgcli/main.py
+++ b/pgcli/main.py
@@ -1634,9 +1634,23 @@ def cli(
         service = database[8:]
     elif os.getenv("PGSERVICE") is not None:
         service = os.getenv("PGSERVICE")
-    # because option --ping, --list or -l are not supposed to have a db name
+    # because option --ping, --list or -l are not supposed to have a db name.
+    # A connection string is not a db name though: a URI or a key=value conninfo
+    # carries the whole connection (host, user, port, sslmode, ...), so replacing
+    # it with "postgres" would throw all of that away and fall back to a local
+    # socket connection as the OS user. Only a plain db name is discarded here;
+    # a connection string that names no database gets "postgres" for the
+    # listing, since libpq would otherwise default to the OS user name.
+    is_conn_string = "://" in database or ("=" in database and service is None)
     if list_databases or ping_database:
-        database = "postgres"
+        if not is_conn_string:
+            database = "postgres"
+        else:
+            try:
+                if not conninfo_to_dict(database).get("dbname"):
+                    database = make_conninfo(database, dbname="postgres")
+            except Exception:
+                pass  # invalid conninfo: let the connection attempt report it
 
     cfg = load_config(pgclirc, config_full_path)
     if dsn != "":
diff --git a/tests/test_main.py b/tests/test_main.py
index ba990631a..5595c504d 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -6,6 +6,7 @@
 from unittest import mock
 
 import pytest
+from click.testing import CliRunner
 
 try:
     import setproctitle
@@ -13,6 +14,7 @@
     setproctitle = None
 
 from pgcli.main import (
+    cli,
     obfuscate_process_password,
     duration_in_words,
     format_output,
@@ -23,6 +25,7 @@
     COLOR_CODE_REGEX,
 )
 from pgcli.pgexecute import PGExecute
+from psycopg.conninfo import conninfo_to_dict
 from pgspecial.main import PAGER_OFF, PAGER_LONG_OUTPUT, PAGER_ALWAYS
 from utils import dbtest, run
 from collections import namedtuple
@@ -701,3 +704,65 @@ def test_get_editor_precedence():
     # Nothing set -> None, so click uses its platform default.
     with mock.patch.dict(os.environ, {}, clear=True):
         assert get_editor() is None
+
+
+def _cli_conn_target(argv, tmpdir):
+    """Run cli() with argv and report which connect_* path it took."""
+    rc = tmpdir.join("rcfile")
+    rc.write("[main]\n")
+    runner = CliRunner()
+    with (
+        mock.patch.object(PGCli, "connect_uri", side_effect=RuntimeError("stop")) as mock_uri,
+        mock.patch.object(PGCli, "connect_dsn", side_effect=RuntimeError("stop")) as mock_dsn,
+        mock.patch.object(PGCli, "connect", side_effect=RuntimeError("stop")) as mock_plain,
+    ):
+        runner.invoke(cli, argv + ["--pgclirc", str(rc)])
+    if mock_uri.called:
+        return "uri", mock_uri.call_args
+    if mock_dsn.called:
+        return "dsn", mock_dsn.call_args
+    if mock_plain.called:
+        return "plain", mock_plain.call_args
+    return "none", None
+
+
+def test_list_databases_keeps_uri(tmpdir):
+    """-l must not discard a connection URI: doing so fell back to a local
+    socket connection as the OS user."""
+    uri = "postgresql://someuser@somehost:6000/somedb"
+    path, call = _cli_conn_target([uri, "-l"], tmpdir)
+    assert path == "uri"
+    assert call.args[0] == uri
+
+
+def test_list_databases_keeps_kv_conninfo(tmpdir):
+    """Same for a key=value conninfo string, which carries sslmode and friends."""
+    kv = "host=somehost port=6000 user=someuser dbname=somedb sslmode=verify-ca"
+    path, call = _cli_conn_target([kv, "-l"], tmpdir)
+    assert path == "dsn"
+    assert call.args[0] == kv
+
+
+def test_ping_keeps_uri(tmpdir):
+    """--ping handles connection strings the same way as -l."""
+    uri = "postgresql://someuser@somehost:6000/somedb"
+    path, call = _cli_conn_target([uri, "--ping"], tmpdir)
+    assert path == "uri"
+    assert call.args[0] == uri
+
+
+def test_list_databases_conn_string_without_dbname_gets_postgres(tmpdir):
+    """A connection string naming no database gets "postgres" for the listing,
+    instead of libpq defaulting to the OS user name."""
+    kv = "host=somehost user=someuser sslmode=verify-ca"
+    path, call = _cli_conn_target([kv, "-l"], tmpdir)
+    assert path == "dsn"
+    assert conninfo_to_dict(call.args[0])["dbname"] == "postgres"
+    assert conninfo_to_dict(call.args[0])["sslmode"] == "verify-ca"  # rest preserved
+
+
+def test_list_databases_discards_plain_dbname(tmpdir):
+    """A plain db name is still discarded by -l."""
+    path, call = _cli_conn_target(["mydb", "-l"], tmpdir)
+    assert path == "plain"
+    assert call.args[0] == "postgres"