diff --git a/README.md b/README.md
index 756fe4a..51f694c 100644
--- a/README.md
+++ b/README.md
@@ -27,10 +27,10 @@ API use:
         application:ensure_all_started(pgapp).
         pgapp:connect([{size, 10}, {database, "mydb"}, {username, "foo"}, {password, "bar"}]).
         pgapp:equery("select current_date", []),
-        pgapp:with_transaction(fun() ->
-                                     pgapp:squery("update ..."),
-                                     pgapp:squery("delete from ..."),
-                                     pgapp:equery("select ? from ?", ["*", Table])
+        pgapp:with_transaction(fun(Conn) ->
+                                     pgapp:squery(Conn, "update ..."),
+                                     pgapp:squery(Conn, "delete from ..."),
+                                     pgapp:equery(Conn, "select ? from ?", ["*", Table])
                                end).
 
     - Multi pool:
diff --git a/src/pgapp.erl b/src/pgapp.erl
index 04234e0..265226a 100644
--- a/src/pgapp.erl
+++ b/src/pgapp.erl
@@ -42,6 +42,10 @@ equery(Sql, Params) ->
             (PoolName :: atom(),
              Sql::epgsql:sql_query(),
              Params   :: list(epgsql:bind_param()))
+            -> epgsql:reply(epgsql:equery_row()) | {error, Reason :: any()};
+            (Conn :: pid(),
+             Sql::epgsql:sql_query(),
+             Params   :: list(epgsql:bind_param()))
             -> epgsql:reply(epgsql:equery_row()) | {error, Reason :: any()}.
 equery(P1, P2, P3) ->
     pgapp_worker:equery(P1, P2, P3).
@@ -66,12 +70,14 @@ squery(Sql) ->
                [epgsql:reply(epgsql:squery_row())] | {error, Reason :: any()};
             (PoolName :: atom(),
              Sql::epgsql:sql_query())
+            -> epgsql:reply(epgsql:squery_row()) |
+               [epgsql:reply(epgsql:squery_row())] | {error, Reason :: any()};
+            (Conn :: pid(),
+             Sql::epgsql:sql_query())
             -> epgsql:reply(epgsql:squery_row()) |
                [epgsql:reply(epgsql:squery_row())] | {error, Reason :: any()}.
-squery(PoolName, Sql) when is_atom(PoolName) ->
-    pgapp_worker:squery(PoolName, Sql);
-squery(Sql, Timeout) ->
-    pgapp_worker:squery(Sql, Timeout).
+squery(P1, P2) ->
+    pgapp_worker:squery(P1, P2).
 
 -spec squery(PoolName :: atom(),
              Sql      :: epgsql:sql_query(),
@@ -81,29 +87,35 @@ squery(Sql, Timeout) ->
 squery(PoolName, Sql, Timeout) ->
     pgapp_worker:squery(PoolName, Sql, Timeout).
 
--spec with_transaction(Function :: fun(() -> Reply))
+-spec with_transaction(Function :: fun((pid()) -> Reply))
                       -> Reply | {rollback | error, any()} when Reply :: any().
-with_transaction(Fun) when is_function(Fun, 0) ->
+with_transaction(Fun) when is_function(Fun, 1) ->
     with_transaction(epgsql_pool, Fun).
 
 -spec with_transaction(PoolName :: atom(),
-                       Function :: fun(() -> Reply))
+                       Function :: fun((pid()) -> Reply))
+                      -> Reply | {rollback | error, any()} when Reply :: any();
+                      (Conn :: pid(),
+                       Function :: fun((pid()) -> Reply))
                       -> Reply | {rollback | error, any()} when Reply :: any();
-                      (Function :: fun(() -> Reply),
+                      (Function :: fun((pid()) -> Reply),
                        Timeout  :: timeout())
                       -> Reply | {rollback | error, any()} when Reply :: any().
-with_transaction(PoolName, Fun) when is_function(Fun, 0);
-                                     is_atom(PoolName) ->
-    pgapp_worker:with_transaction(PoolName, Fun);
-with_transaction(Fun, Timeout) when is_function(Fun, 0) ->
+with_transaction(P1, Fun) when is_function(Fun, 1) ->
+    pgapp_worker:with_transaction(P1, Fun);
+with_transaction(Fun, Timeout) when is_function(Fun, 1) ->
     pgapp_worker:with_transaction(epgsql_pool, Fun, Timeout).
 
 -spec with_transaction(PoolName :: atom(),
-                       Function :: fun(() -> Reply),
+                       Function :: fun((pid()) -> Reply),
+                       Timeout  :: atom() | non_neg_integer())
+                      -> Reply | {rollback | error, any()} when Reply :: any();
+                      (Conn :: pid(),
+                       Function :: fun((pid()) -> Reply),
                        Timeout  :: atom() | non_neg_integer())
                       -> Reply | {rollback | error, any()} when Reply :: any().
-with_transaction(PoolName, Fun, Timeout) when is_function(Fun, 0) ->
-    pgapp_worker:with_transaction(PoolName, Fun, Timeout).
+with_transaction(P1, Fun, Timeout) when is_function(Fun, 1) ->
+    pgapp_worker:with_transaction(P1, Fun, Timeout).
 
 %%--------------------------------------------------------------------
 %% @doc
diff --git a/src/pgapp_worker.erl b/src/pgapp_worker.erl
index 5684498..3b2524f 100644
--- a/src/pgapp_worker.erl
+++ b/src/pgapp_worker.erl
@@ -26,18 +26,13 @@
 -define(MAXIMUM_DELAY, 5 * 60 * 1000). % Five minutes
 -define(TIMEOUT, 5 * 1000).
 
--define(STATE_VAR, '$pgapp_state').
-
 squery(Sql) ->
-    case get(?STATE_VAR) of
-        undefined ->
-            squery(epgsql_pool, Sql);
-        Conn ->
-            epgsql:squery(Conn, Sql)
-    end.
+    squery(epgsql_pool, Sql).
 
 squery(PoolName, Sql) when is_atom(PoolName) ->
     squery(PoolName, Sql, ?TIMEOUT);
+squery(Conn, Sql) when is_pid(Conn) ->
+    epgsql:squery(Conn, Sql);
 squery(Sql, Timeout) ->
     squery(epgsql_pool, Sql, Timeout).
 
@@ -48,15 +43,12 @@ squery(PoolName, Sql, Timeout) ->
                            end, Timeout).
 
 equery(Sql, Params) ->
-    case get(?STATE_VAR) of
-        undefined ->
-            equery(epgsql_pool, Sql, Params);
-        Conn ->
-            epgsql:equery(Conn, Sql, Params)
-    end.
+    equery(epgsql_pool, Sql, Params).
 
 equery(PoolName, Sql, Params) when is_atom(PoolName) ->
     equery(PoolName, Sql, Params, ?TIMEOUT);
+equery(Conn, Sql, Params) when is_pid(Conn) ->
+    epgsql:equery(Conn, Sql, Params);
 equery(Sql, Params, Timeout) ->
     equery(epgsql_pool, Sql, Params, Timeout).
 
@@ -70,12 +62,14 @@ equery(PoolName, Sql, Params, Timeout) ->
 with_transaction(PoolName, Fun) ->
     with_transaction(PoolName, Fun, ?TIMEOUT).
 
-with_transaction(PoolName, Fun, Timeout) ->
+with_transaction(PoolName, Fun, Timeout) when is_atom(PoolName) ->
     middle_man_transaction(PoolName,
                            fun (W) ->
                                    gen_server:call(W, {transaction, Fun},
                                                    Timeout)
-                           end, Timeout).
+                           end, Timeout);
+with_transaction(Conn, Fun, _Timeout) when is_pid(Conn) ->
+    epgsql:with_transaction(Conn, Fun).
 
 middle_man_transaction(Pool, Fun, Timeout) ->
     Tag = make_ref(),
@@ -112,9 +106,7 @@ handle_call({equery, Sql, Params}, _From,
     {reply, epgsql:equery(Conn, Sql, Params), State};
 handle_call({transaction, Fun}, _From,
             #state{conn = Conn} = State) ->
-    put(?STATE_VAR, Conn),
-    Result = epgsql:with_transaction(Conn, fun(_) -> Fun() end),
-    erase(?STATE_VAR),
+    Result = epgsql:with_transaction(Conn, Fun),
     {reply, Result, State}.
 
 handle_cast(reconnect, State) ->