diff --git a/src/SqlClient.DesignTime/DesignTime.fs b/src/SqlClient.DesignTime/DesignTime.fs
index 735d6edc..ce3393a1 100644
--- a/src/SqlClient.DesignTime/DesignTime.fs
+++ b/src/SqlClient.DesignTime/DesignTime.fs
@@ -761,10 +761,9 @@ type DesignTime private() =
                     <@@ let cmd = (%%command : ISqlCommand)
                         cmd.Raw.Connection @@>
 
-                <@@ do
-                        use create = (%%connection : SqlConnection).CreateCommand(CommandText = tempTableDefinitions)
-                        create.ExecuteNonQuery() |> ignore
-
+                <@@ use openedConn = (%%connection : SqlConnection).UseLocally()
+                    use create = (%%connection : SqlConnection).CreateCommand(CommandText = tempTableDefinitions)
+                    create.ExecuteNonQuery() |> ignore
                     (%%loadValues exprArgs connection)
                     ignore() @@>)
 
diff --git a/tests/SqlClient.Tests/TempTableTests.fs b/tests/SqlClient.Tests/TempTableTests.fs
index 52deeac2..e00b5e36 100644
--- a/tests/SqlClient.Tests/TempTableTests.fs
+++ b/tests/SqlClient.Tests/TempTableTests.fs
@@ -17,6 +17,28 @@ type TempTable =
         ConnectionStringOrName =
             ConnectionStrings.AdventureWorksLiteral>
 
+[<Fact>]
+let usingTempTableWithConnectionString() =
+    // Regression test for issue #306: LoadTempTables should auto-open the connection
+    use cmd = new TempTable(ConnectionStrings.AdventureWorksLiteral)
+
+    cmd.LoadTempTables(
+        Temp =
+            [ TempTable.Temp(Id = 1, Name = Some "cat")
+              TempTable.Temp(Id = 2, Name = Some "dog") ])
+
+    let actual =
+        cmd.Execute()
+        |> Seq.map(fun x -> x.Id, x.Name)
+        |> Seq.toList
+
+    let expected = [
+        1, Some "cat"
+        2, Some "dog"
+    ]
+
+    Assert.Equal<_ list>(expected, actual)
+
 [<Fact>]
 let usingTempTable() =
     use conn = new SqlConnection(ConnectionStrings.AdventureWorksLiteral)