diff --git a/repo2docker/buildpacks/_rstudio.py b/repo2docker/buildpacks/_rstudio.py
index d0ba10f7..e0e59b56 100644
--- a/repo2docker/buildpacks/_rstudio.py
+++ b/repo2docker/buildpacks/_rstudio.py
@@ -77,6 +77,11 @@ def load_rstudio_yaml(path):
         return YAML().load(f)
 
 
+def parse_r_version(r_version):
+    """Parse an R version pin; conda pins like "r-base=4.4.*" leave a trailing dot."""
+    return V(r_version.rstrip("."))
+
+
 def rstudio_server_installer(r_version, rstudio_config):
     """Return (url, sha256) of the RStudio Server .deb to install.
 
@@ -103,6 +108,6 @@ def rstudio_server_installer(r_version, rstudio_config):
                 f"does not exist: {url} returned {resp.status_code}"
             )
         return url, sha256
-    if r_version and V(r_version) < V(RSTUDIO_MIN_R_VERSION):
+    if r_version and parse_r_version(r_version) < V(RSTUDIO_MIN_R_VERSION):
         return LEGACY_RSTUDIO_URL, LEGACY_RSTUDIO_SHA256
     return fetch_latest_rstudio_server()
diff --git a/tests/unit/test_rstudio.py b/tests/unit/test_rstudio.py
index 0ca205f7..54791363 100644
--- a/tests/unit/test_rstudio.py
+++ b/tests/unit/test_rstudio.py
@@ -50,7 +50,7 @@ def clear_fetch_cache():
     fetch_latest_rstudio_server.cache_clear()
 
 
-@pytest.mark.parametrize("r_version", ["3.3.3", "3.5.3"])
+@pytest.mark.parametrize("r_version", ["3.3.3", "3.5.3", "3.5."])
 def test_legacy_rstudio_for_old_r(r_version):
     assert rstudio_server_installer(r_version, None) == (
         LEGACY_RSTUDIO_URL,
@@ -58,7 +58,7 @@ def test_legacy_rstudio_for_old_r(r_version):
     )
 
 
-@pytest.mark.parametrize("r_version", ["", "3.6", "4.2.1"])
+@pytest.mark.parametrize("r_version", ["", "3.6", "4.2.1", "4.4."])
 def test_latest_rstudio(r_version):
     with patch("repo2docker.buildpacks._rstudio.requests.get") as mock_get:
         mock_get.return_value.json.return_value = DOWNLOADS_JSON