diff --git a/cli/src/common.c b/cli/src/common.c
index c8998ed648..cbf6f07662 100644
--- a/cli/src/common.c
+++ b/cli/src/common.c
@@ -862,3 +862,24 @@ nmc_vlan_parse_priority_maps (const char *priority_map,
 	return mapping;
 }
 
+const char *
+nmc_bond_validate_mode (const char *mode, GError **error)
+{
+	unsigned long mode_int;
+	static const char *valid_modes[] = { "balance-rr",
+	                                     "active-backup",
+	                                     "balance-xor",
+	                                     "broadcast",
+	                                     "802.3ad",
+	                                     "balance-tlb",
+	                                     "balance-alb",
+	                                     NULL };
+	if (nmc_string_to_uint (mode, TRUE, 0, 6, &mode_int)) {
+		/* Translate bonding mode numbers to mode names:
+		 * https://www.kernel.org/doc/Documentation/networking/bonding.txt
+		 */
+		return valid_modes[mode_int];
+	} else
+		return nmc_string_is_valid (mode, valid_modes, error);
+}
+
diff --git a/cli/src/common.h b/cli/src/common.h
index 5914c8c25c..69a81d5878 100644
--- a/cli/src/common.h
+++ b/cli/src/common.h
@@ -51,4 +51,6 @@ nmc_vlan_parse_priority_maps (const char *priority_map,
                               NMVlanPriorityMap map_type,
                               GError **error);
 
+const char *nmc_bond_validate_mode (const char *mode, GError **error);
+
 #endif /* NMC_COMMON_H */
diff --git a/cli/src/connections.c b/cli/src/connections.c
index 0c187c4905..909cb029a0 100644
--- a/cli/src/connections.c
+++ b/cli/src/connections.c
@@ -247,7 +247,8 @@ usage_connection_add (void)
 	         "                  [ingress <ingress priority mapping>]\n"
 	         "                  [egress <egress priority mapping>]\n"
 	         "                  [mtu <MTU>]\n\n"
-	         "    bond:         [mode balance-rr|active-backup|balance-xor|broadcast|802.3ad|balance-tlb|balance-alb]\n"
+	         "    bond:         [mode balance-rr (0) | active-backup (1) | balance-xor (2) | broadcast (3) |\n"
+	         "                        802.3ad    (4) | balance-tlb   (5) | balance-alb (6)]\n"
 	         "                  [miimon <num>]\n"
 	         "                  [downdelay <num>]\n"
 	         "                  [updelay <num>]\n"
@@ -2435,8 +2436,17 @@ cleanup_vlan:
 
 		/* Set bond options */
 		g_object_set (s_bond, NM_SETTING_BOND_INTERFACE_NAME, bond_ifname, NULL);
-		if (bond_mode)
+		if (bond_mode) {
+			GError *err = NULL;
+			if (!(bond_mode = nmc_bond_validate_mode (bond_mode, &err))) {
+				g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
+				             _("Error: 'mode': %s."), err->message);
+				g_clear_error (&err);
+				g_free (bond_ifname);
+				return FALSE;
+			}
 			nm_setting_bond_add_option (s_bond, NM_SETTING_BOND_OPTION_MODE, bond_mode);
+		}
 		if (bond_miimon)
 			nm_setting_bond_add_option (s_bond, NM_SETTING_BOND_OPTION_MIIMON, bond_miimon);
 		if (bond_downdelay)