diff --git a/mssql_test.go b/mssql_test.go
index 45d59b1..520849a 100644
--- a/mssql_test.go
+++ b/mssql_test.go
@@ -1978,3 +1978,154 @@ func TestMSSQLQueryContextCancel(t *testing.T) {
 		t.Fatalf("Unexpected error value: should=%s, is=%s", context.Canceled, err)
 	}
 }
+
+// https://github.com/alexbrainman/odbc/issues/178
+// verify that inserting unicode text into an NVARCHAR column
+// with a specified collation preserves the original characters when
+// the parameter is sent from Go.  The collation on NVARCHAR only affects
+// comparisons and sort order, not storage.  This test reproduces
+// behavior originally reported in issue #178.
+func TestMSSQLNVarcharCollationPreservesUnicode(t *testing.T) {
+	db, sc, err := mssqlConnect()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer closeDB(t, db, sc, sc)
+
+	type testStruct struct {
+		name    string
+		collate string
+		poem    string
+	}
+
+	testCases := []testStruct{
+		{
+			name:    "zh_tw_big5",
+			collate: "Chinese_Taiwan_Bopomofo_CI_AS",
+			poem:    "花間一壺酒，獨酌無相親。",
+		},
+		{
+			name:    "zh_cn_gbk",
+			collate: "Chinese_PRC_90_CI_AS",
+			poem:    "花间一壶酒，独酌无相亲。",
+		},
+		{
+			name:    "ja_jp",
+			collate: "Japanese_CI_AS",
+			poem:    "月日は百代の過客にして、行かふ年も又旅人也",
+		},
+		{
+			name:    "ko_kr",
+			collate: "Korean_Wansung_CI_AS",
+			poem:    "꽃 사이 놓인 한 동이 술을 친한 이 없이 혼자 마시네.",
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			db.Exec("drop table dbo.temp")
+			exec(t, db, "create table dbo.temp (poem nvarchar(200) collate "+tc.collate+")")
+
+			// when the column is VARCHAR with a specific collation, converting
+			// the parameter on the server side using that collation ensures the
+			// NVARCHAR value we send is mapped into the correct code page.  if
+			// we simply send the parameter as NVARCHAR and insert directly into a
+			// VARCHAR column the conversion uses the database default collation and
+			// we lose characters for languages not covered by that code page.
+			//
+			// cast the incoming nvarchar parameter to varchar and give the
+			// cast the desired collation.  this way the conversion from
+			// Unicode to the column code page uses the correct collation,
+			// not the database default.
+			//
+			// column is NVARCHAR so we can insert directly without worrying
+			// about code page conversions; the collation on nvarchar only
+			// affects comparisons and sort order, not storage.
+			stmt, err := db.Prepare("insert into dbo.temp (poem) values (?)")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer stmt.Close()
+
+			if _, err := stmt.Exec(tc.poem); err != nil {
+				t.Fatal(err)
+			}
+
+			var got string
+			if err := db.QueryRow("select cast(poem as nvarchar(max)) from dbo.temp").Scan(&got); err != nil {
+				t.Fatal(err)
+			}
+			if got != tc.poem {
+				t.Fatalf("poem mismatch, want=%v, got=%v", tc.poem, got)
+			}
+
+			exec(t, db, "drop table dbo.temp")
+		})
+	}
+}
+
+// https://github.com/alexbrainman/odbc/issues/178
+// verify that an SQL statement which provides a parameter description
+// causes BindValue to honor the described size rather than the length of
+// the actual string.  this test will fail if the size override lines in
+// param.go are removed (they were added in #178).
+func TestMSSQLDescribeParameterSize(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skip in short mode")
+	}
+	db, _, err := mssqlConnectWithParams(newConnParams())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// first, make sure the driver actually describes the parameter and returns
+	// the expected size.  we use the Raw method to gain access to the
+	// underlying *Conn and call PrepareODBCStmt directly.
+	conn, err2 := db.Conn(context.Background())
+	if err2 != nil {
+		t.Fatalf("failed to get raw connection: %v", err2)
+	}
+	defer conn.Close()
+	err = conn.Raw(func(dc interface{}) error {
+		c := dc.(*Conn)
+		stmt, err := c.PrepareODBCStmt("select cast(? as varchar(5))")
+		if err != nil {
+			return err
+		}
+		if len(stmt.Parameters) != 1 {
+			return fmt.Errorf("unexpected param count %d", len(stmt.Parameters))
+		}
+		p := stmt.Parameters[0]
+		if !p.isDescribed || p.Size != 5 {
+			return fmt.Errorf("expected described size 5, got isDescribed=%v size=%d", p.isDescribed, p.Size)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// intercept SQLBindParameter to capture the size argument used by BindValue
+	var boundSize api.SQLULEN
+	orig := sqlBindParameter
+	sqlBindParameter = func(h api.SQLHSTMT, paramNumber api.SQLUSMALLINT,
+		inputOutputType api.SQLSMALLINT, cType api.SQLSMALLINT, sqlType api.SQLSMALLINT,
+		size api.SQLULEN, decimal api.SQLSMALLINT,
+		buffer api.SQLPOINTER, bufferLength api.SQLLEN, strLenOrIndPtr *api.SQLLEN,
+	) api.SQLRETURN {
+		boundSize = size
+		return orig(h, paramNumber, inputOutputType, cType, sqlType,
+			size, decimal, buffer, bufferLength, strLenOrIndPtr)
+	}
+	defer func() { sqlBindParameter = orig }()
+
+	// execute the statement once; the cast will raise a truncation error when
+	// the input exceeds five characters, but that is irrelevant to capturing
+	// the bound size.
+	_, _ = db.Exec("select cast(? as varchar(5))", "abcdef")
+	if boundSize != 5 {
+		t.Fatalf("expected bound size 5, got %d", boundSize)
+	}
+}
diff --git a/param.go b/param.go
index e5dd8ba..ea279f8 100644
--- a/param.go
+++ b/param.go
@@ -32,6 +32,9 @@ func (p *Parameter) StoreStrLen_or_IndPtr(v api.SQLLEN) *api.SQLLEN {
 
 }
 
+// exposeable hook for binding; tests override this to capture arguments.
+var sqlBindParameter = api.SQLBindParameter
+
 func (p *Parameter) BindValue(h api.SQLHSTMT, idx int, v driver.Value, conn *Conn) error {
 	// TODO(brainman): Reuse memory for previously bound values. If memory
 	// is reused, we, probably, do not need to call SQLBindParameter either.
@@ -70,6 +73,9 @@ func (p *Parameter) BindValue(h api.SQLHSTMT, idx int, v driver.Value, conn *Con
 				sqltype = api.SQL_WLONGVARCHAR
 			case p.isDescribed:
 				sqltype = p.SQLType
+				if p.Size != 0 {
+					size = p.Size
+				}
 			case size <= 1:
 				sqltype = api.SQL_WVARCHAR
 			default:
@@ -163,7 +169,7 @@ func (p *Parameter) BindValue(h api.SQLHSTMT, idx int, v driver.Value, conn *Con
 	default:
 		return fmt.Errorf("unsupported type %T", v)
 	}
-	ret := api.SQLBindParameter(h, api.SQLUSMALLINT(idx+1),
+	ret := sqlBindParameter(h, api.SQLUSMALLINT(idx+1),
 		api.SQL_PARAM_INPUT, ctype, sqltype, size, decimal,
 		api.SQLPOINTER(buf), buflen, plen)
 	if IsError(ret) {