diff --git a/sys/geom/part/g_part_mbr.c b/sys/geom/part/g_part_mbr.c
index 126210b5629c..f3e57707b4f6 100644
--- a/sys/geom/part/g_part_mbr.c
+++ b/sys/geom/part/g_part_mbr.c
@@ -119,6 +119,7 @@ static struct g_part_mbr_alias {
 	{ DOSPTYP_EXT,		G_PART_ALIAS_EBR },
 	{ DOSPTYP_NTFS,		G_PART_ALIAS_MS_NTFS },
 	{ DOSPTYP_FAT32,	G_PART_ALIAS_MS_FAT32 },
+	{ DOSPTYP_LDM,		G_PART_ALIAS_MS_LDM_DATA },
 	{ DOSPTYP_LINSWP,	G_PART_ALIAS_LINUX_SWAP },
 	{ DOSPTYP_LINUX,	G_PART_ALIAS_LINUX_DATA },
 	{ DOSPTYP_LINLVM,	G_PART_ALIAS_LINUX_LVM },
diff --git a/sys/sys/diskmbr.h b/sys/sys/diskmbr.h
index 0caf0d773e85..dcb39185ba1a 100644
--- a/sys/sys/diskmbr.h
+++ b/sys/sys/diskmbr.h
@@ -49,6 +49,7 @@
 #define	DOSPTYP_FAT32	0x0b	/* FAT32 partition */
 #define	DOSPTYP_EXTLBA	0x0f	/* DOS extended partition */
 #define	DOSPTYP_PPCBOOT	0x41	/* PReP/CHRP boot partition */
+#define	DOSPTYP_LDM	0x42	/* Win2k dynamic extended partition */
 #define	DOSPTYP_386BSD	0xa5	/* 386BSD partition type */
 #define	DOSPTYP_LINSWP	0x82	/* Linux swap partition */
 #define	DOSPTYP_LINUX	0x83	/* Linux partition */