diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index d7b4d2393a1..e1a1d5a1c58 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.270 2008/11/14 22:58:51 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.271 2008/11/25 19:30:42 tgl Exp $ -->
 
 <chapter id="libpq">
  <title><application>libpq</application> - C Library</title>
@@ -5820,17 +5820,6 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
      </para>
     </listitem>
 
-    <listitem>
-     <para>
-      <indexterm>
-       <primary><envar>PGINTERVALSTYLE</envar></primary>
-      </indexterm>
-      <envar>PGINTERVALSTYLE</envar> sets the default style of interval
-      representation.  (Equivalent to <literal>SET intervalstyle TO
-      ...</literal>.)
-     </para>
-    </listitem>
-
     <listitem>
      <para>
       <indexterm>
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index e1376dc0173..2cfe36e3a22 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.368 2008/11/13 09:45:24 mha Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.369 2008/11/25 19:30:42 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -213,9 +213,6 @@ static const PQEnvironmentOption EnvironmentOptions[] =
 	{
 		"PGDATESTYLE", "datestyle"
 	},
-	{
-		"PGINTERVALSTYLE", "intervalstyle"
-	},
 	{
 		"PGTZ", "timezone"
 	},
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index d063602c7e6..f64e00b643f 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.51 2008/11/25 11:49:35 petere Exp $
+ * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.52 2008/11/25 19:30:42 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -716,7 +716,23 @@ initialize_environment(void)
 	 */
 	putenv("PGTZ=PST8PDT");
 	putenv("PGDATESTYLE=Postgres, MDY");
-	putenv("PGINTERVALSTYLE=postgres_verbose");
+
+	/*
+	 * Likewise set intervalstyle to ensure consistent results.  This is a
+	 * bit more painful because we must use PGOPTIONS, and we want to preserve
+	 * the user's ability to set other variables through that.
+	 */
+	{
+		const char *my_pgoptions = "--intervalstyle=postgres_verbose";
+		const char *old_pgoptions = getenv("PGOPTIONS");
+		char   *new_pgoptions;
+
+		if (!old_pgoptions)
+			old_pgoptions = "";
+		new_pgoptions = malloc(strlen(old_pgoptions) + strlen(my_pgoptions) + 12);
+		sprintf(new_pgoptions, "PGOPTIONS=%s %s", old_pgoptions, my_pgoptions);
+		putenv(new_pgoptions);
+	}
 
 	if (temp_install)
 	{