diff --git a/Makefile.local b/Makefile.local
index 28286597..a3a19dea 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -7,6 +7,7 @@ notmuch_client_srcs =		\
 	gmime-filter-reply.c	\
 	notmuch.c		\
 	notmuch-config.c	\
+	notmuch-count.c		\
 	notmuch-dump.c		\
 	notmuch-new.c		\
 	notmuch-reply.c		\
diff --git a/lib/notmuch.h b/lib/notmuch.h
index a61cd020..260cc22d 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -468,6 +468,14 @@ notmuch_threads_advance (notmuch_threads_t *threads);
 void
 notmuch_threads_destroy (notmuch_threads_t *threads);
 
+/* Return an estimate of the number of messages matching a search
+ *
+ * This function performs a search and returns Xapian's best
+ * guess as to number of matching messages.
+ */
+unsigned
+notmuch_query_count_messages (notmuch_query_t *query);
+ 
 /* Get the thread ID of 'thread'.
  *
  * The returned string belongs to 'thread' and as such, should not be
diff --git a/lib/query.cc b/lib/query.cc
index 86167352..686d75f9 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -279,3 +279,55 @@ notmuch_threads_destroy (notmuch_threads_t *threads)
 {
     talloc_free (threads);
 }
+
+unsigned
+notmuch_query_count_messages (notmuch_query_t *query)
+{
+    notmuch_database_t *notmuch = query->notmuch;
+    const char *query_string = query->query_string;
+    Xapian::doccount count;
+
+    try {
+	Xapian::Enquire enquire (*notmuch->xapian_db);
+	Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
+						   _find_prefix ("type"),
+						   "mail"));
+	Xapian::Query string_query, final_query;
+	Xapian::MSet mset;
+	unsigned int flags = (Xapian::QueryParser::FLAG_BOOLEAN |
+			      Xapian::QueryParser::FLAG_PHRASE |
+			      Xapian::QueryParser::FLAG_LOVEHATE |
+			      Xapian::QueryParser::FLAG_BOOLEAN_ANY_CASE |
+			      Xapian::QueryParser::FLAG_WILDCARD |
+			      Xapian::QueryParser::FLAG_PURE_NOT);
+
+	if (strcmp (query_string, "") == 0) {
+	    final_query = mail_query;
+	} else {
+	    string_query = notmuch->query_parser->
+		parse_query (query_string, flags);
+	    final_query = Xapian::Query (Xapian::Query::OP_AND,
+					 mail_query, string_query);
+	}
+
+	enquire.set_weighting_scheme(Xapian::BoolWeight());
+	enquire.set_docid_order(Xapian::Enquire::ASCENDING);
+
+#if DEBUG_QUERY
+	fprintf (stderr, "Final query is:\n%s\n", final_query.get_description().c_str());
+#endif
+
+	enquire.set_query (final_query);
+
+	mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
+
+	count = mset.get_matches_estimated();
+
+    } catch (const Xapian::Error &error) {
+	fprintf (stderr, "A Xapian exception occurred: %s\n",
+		 error.get_msg().c_str());
+	fprintf (stderr, "Query string was: %s\n", query->query_string);
+    }
+
+    return count;
+}
diff --git a/notmuch-client.h b/notmuch-client.h
index 4fe182ee..c04eaeb4 100644
--- a/notmuch-client.h
+++ b/notmuch-client.h
@@ -92,6 +92,9 @@ chomp_newline (char *str)
 	str[strlen(str)-1] = '\0';
 }
 
+int
+notmuch_count_command (void *ctx, int argc, char *argv[]);
+
 int
 notmuch_dump_command (void *ctx, int argc, char *argv[]);
 
diff --git a/notmuch-count.c b/notmuch-count.c
new file mode 100644
index 00000000..77aa4338
--- /dev/null
+++ b/notmuch-count.c
@@ -0,0 +1,110 @@
+/* notmuch - Not much of an email program, (just index and search)
+ *
+ * Copyright © 2009 Carl Worth
+ * Copyright © 2009 Keith Packard
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Keith Packard <keithp@keithp.com>
+ */
+
+#include "notmuch-client.h"
+
+int
+notmuch_count_command (void *ctx, int argc, char *argv[])
+{
+    notmuch_config_t *config;
+    notmuch_database_t *notmuch;
+    notmuch_query_t *query;
+    char *query_str;
+    int i;
+#if 0
+    char *opt, *end;
+    int i, first = 0, max_threads = -1;
+    notmuch_sort_t sort = NOTMUCH_SORT_NEWEST_FIRST;
+#endif
+
+    for (i = 0; i < argc && argv[i][0] == '-'; i++) {
+	if (strcmp (argv[i], "--") == 0) {
+	    i++;
+	    break;
+	}
+#if 0
+	if (STRNCMP_LITERAL (argv[i], "--first=") == 0) {
+	    opt = argv[i] + sizeof ("--first=") - 1;
+	    first = strtoul (opt, &end, 10);
+	    if (*opt == '\0' || *end != '\0') {
+		fprintf (stderr, "Invalid value for --first: %s\n", opt);
+		return 1;
+	    }
+	} else if (STRNCMP_LITERAL (argv[i], "--max-threads=") == 0) {
+	    opt = argv[i] + sizeof ("--max-threads=") - 1;
+	    max_threads = strtoul (opt, &end, 10);
+	    if (*opt == '\0' || *end != '\0') {
+		fprintf (stderr, "Invalid value for --max-threads: %s\n", opt);
+		return 1;
+	    }
+	} else if (STRNCMP_LITERAL (argv[i], "--sort=") == 0) {
+	    opt = argv[i] + sizeof ("--sort=") - 1;
+	    if (strcmp (opt, "oldest-first") == 0) {
+		sort = NOTMUCH_SORT_OLDEST_FIRST;
+	    } else if (strcmp (opt, "newest-first") == 0) {
+		sort = NOTMUCH_SORT_NEWEST_FIRST;
+	    } else {
+		fprintf (stderr, "Invalid value for --sort: %s\n", opt);
+		return 1;
+	    }
+	} else
+#endif
+	{
+	    fprintf (stderr, "Unrecognized option: %s\n", argv[i]);
+	    return 1;
+	}
+    }
+
+    argc -= i;
+    argv += i;
+
+    config = notmuch_config_open (ctx, NULL, NULL);
+    if (config == NULL)
+	return 1;
+
+    notmuch = notmuch_database_open (notmuch_config_get_database_path (config),
+				     NOTMUCH_DATABASE_MODE_READ_ONLY);
+    if (notmuch == NULL)
+	return 1;
+
+    query_str = query_string_from_args (ctx, argc, argv);
+    if (query_str == NULL) {
+	fprintf (stderr, "Out of memory.\n");
+	return 1;
+    }
+    if (*query_str == '\0') {
+	fprintf (stderr, "Error: notmuch count requires at least one count term.\n");
+	return 1;
+    }
+
+    query = notmuch_query_create (notmuch, query_str);
+    if (query == NULL) {
+	fprintf (stderr, "Out of memory\n");
+	return 1;
+    }
+
+    printf ("%u\n", notmuch_query_count_messages(query));
+
+    notmuch_query_destroy (query);
+    notmuch_database_close (notmuch);
+
+    return 0;
+}
diff --git a/notmuch.c b/notmuch.c
index d84cea59..72ca6204 100644
--- a/notmuch.c
+++ b/notmuch.c
@@ -187,6 +187,17 @@ command_t commands[] = {
       "\n"
       "\t\tSee \"notmuch help search-terms\" for details of the search\n"
       "\t\tterms syntax." },
+    { "count", notmuch_count_command,
+      "<search-terms> [...]",
+      "\t\tCount messages matching the search terms.",
+      "\t\tThe number of matching messages is output to stdout.\n"
+      "\n"
+      "\t\tA common use of \"notmuch count\" is to display the count\n"
+      "\t\tof messages matching both a specific tag and either inbox\n"
+      "\t\tor unread\n"
+      "\n"
+      "\t\tSee \"notmuch help search-terms\" for details of the search\n"
+      "\t\tterms syntax." },
     { "reply", notmuch_reply_command,
       "<search-terms> [...]",
       "\t\tConstruct a reply template for a set of messages.",