diff --git a/Makefile.am b/Makefile.am
index b186b90..c7868bb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -65,7 +65,7 @@ bin_iscsi_test_SOURCES = test-tool/iscsi-test.c \
 	test-tool/0153_read16_rdprotect.c \
 	test-tool/0160_readcapacity16_simple.c \
 	test-tool/0170_unmap_simple.c test-tool/0171_unmap_zero.c \
-	test-tool/0180_writesame10_unmap.c
+	test-tool/0180_writesame10_unmap.c test-tool/0181_writesame10_unmap_unaligned.c
 endif
 
 # LD_PRELOAD library.
diff --git a/test-tool/0181_writesame10_unmap_unaligned.c b/test-tool/0181_writesame10_unmap_unaligned.c
new file mode 100644
index 0000000..858ea6d
--- /dev/null
+++ b/test-tool/0181_writesame10_unmap_unaligned.c
@@ -0,0 +1,113 @@
+/* 
+   Copyright (C) 2012 by Ronnie Sahlberg <ronniesahlberg@gmail.com>
+   
+   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 2 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/>.
+*/
+
+#include <stdio.h>
+#include "iscsi.h"
+#include "scsi-lowlevel.h"
+#include "iscsi-test.h"
+
+int T0181_writesame10_unmap_unaligned(const char *initiator, const char *url)
+{ 
+	struct iscsi_context *iscsi;
+	struct scsi_task *task;
+	struct scsi_readcapacity16 *rc16;
+	int ret, i, lun;
+	uint32_t block_size, num_blocks;
+	int lbppb;
+
+	iscsi = iscsi_context_login(initiator, url, &lun);
+	if (iscsi == NULL) {
+		printf("Failed to login to target\n");
+		return -1;
+	}
+
+	/* find the size of the LUN */
+	task = iscsi_readcapacity16_sync(iscsi, lun);
+	if (task == NULL) {
+		printf("Failed to send readcapacity16 command: %s\n", iscsi_get_error(iscsi));
+		ret = -1;
+		goto finished;
+	}
+	if (task->status != SCSI_STATUS_GOOD) {
+		printf("Readcapacity command: failed with sense. %s\n", iscsi_get_error(iscsi));
+		ret = -1;
+		scsi_free_scsi_task(task);
+		goto finished;
+	}
+	rc16 = scsi_datain_unmarshall(task);
+	if (rc16 == NULL) {
+		printf("failed to unmarshall readcapacity16 data. %s\n", iscsi_get_error(iscsi));
+		ret = -1;
+		scsi_free_scsi_task(task);
+		goto finished;
+	}
+
+	if (rc16->lbpme == 0){
+		printf("Logical unit is fully provisioned. Skipping test\n");
+		ret = -1;
+		scsi_free_scsi_task(task);
+		goto finished;
+	}
+
+	block_size = rc16->block_length;
+	num_blocks = rc16->returned_lba;
+	lbppb = 1 << rc16->lbppbe;
+
+	scsi_free_scsi_task(task);
+
+	if (lbppb < 2) {
+		printf("LBPPB==%d  Can not unmap fractional physical block\n", lbppb);
+		ret = -1;
+		goto finished;
+	}
+
+	if (!data_loss) {
+		printf("--dataloss flag is not set. Skipping test\n");
+		ret = -1;
+		goto finished;
+	}
+	
+	ret = 0;
+
+	/* unmap the first 1 - lbppb blocks at the start of the LUN */
+	printf("Unmapping first 1 - (LBPPB-1) blocks ... ");
+	for (i=1; i < lbppb; i++) {
+		task = iscsi_writesame10_sync(iscsi, lun, NULL, 0,
+					0, i,
+					0, 1, 0, 0, 0, 0);
+		if (task == NULL) {
+		        printf("[FAILED]\n");
+			printf("Failed to send WRITESAME10 command: %s\n", iscsi_get_error(iscsi));
+			ret = -1;
+			goto finished;
+		}
+		if (task->status == SCSI_STATUS_GOOD) {
+		        printf("[FAILED]\n");
+			printf("WRITESAME10 command to unmap a fractional physical block should fail\n");
+			ret = -1;
+			scsi_free_scsi_task(task);
+			goto finished;
+		}
+		scsi_free_scsi_task(task);
+	}
+	printf("[OK]\n");
+
+finished:
+	iscsi_logout_sync(iscsi);
+	iscsi_destroy_context(iscsi);
+	return ret;
+}
diff --git a/test-tool/iscsi-test.c b/test-tool/iscsi-test.c
index 80c93e1..992b42c 100644
--- a/test-tool/iscsi-test.c
+++ b/test-tool/iscsi-test.c
@@ -74,6 +74,7 @@ struct scsi_test tests[] = {
 
 /* writesame10*/
 { "T0180_writesame10_unmap",		T0180_writesame10_unmap },
+{ "T0181_writesame10_unmap_unaligned",	T0181_writesame10_unmap_unaligned },
 
 { NULL, NULL }
 };
diff --git a/test-tool/iscsi-test.h b/test-tool/iscsi-test.h
index a4484e0..7a2bcb4 100644
--- a/test-tool/iscsi-test.h
+++ b/test-tool/iscsi-test.h
@@ -49,3 +49,4 @@ int T0170_unmap_simple(const char *initiator, const char *url);
 int T0171_unmap_zero(const char *initiator, const char *url);
 
 int T0180_writesame10_unmap(const char *initiator, const char *url);
+int T0181_writesame10_unmap_unaligned(const char *initiator, const char *url);