diff --git a/lib/astunparse/unparser.py b/lib/astunparse/unparser.py
index 71a9456..87cc866 100644
--- a/lib/astunparse/unparser.py
+++ b/lib/astunparse/unparser.py
@@ -444,8 +444,7 @@ def _Str(self, tree):
 
     format_conversions = {97: 'a', 114: 'r', 115: 's'}
 
-    def _FormattedValue(self, t):
-        # FormattedValue(expr value, int? conversion, expr? format_spec)
+    def _generic_FormattedValue(self, t):
         self.write("{")
         self.dispatch(t.value)
         if t.conversion is not None and t.conversion != -1:
@@ -455,17 +454,33 @@ def _FormattedValue(self, t):
         if t.format_spec is not None:
             self.write(":")
             if isinstance(t.format_spec, ast.Str):
+                # It's ast.Str in 3.6.0
                 self.write(t.format_spec.s)
+            elif isinstance(t.format_spec, ast.JoinedStr):
+                # It's ast.JoinedStr in 3.6.1+
+                for value in t.format_spec.values:
+                    if isinstance(value, ast.Str):
+                        self.write(value.s)
+                    else:
+                        self.dispatch(value)
             else:
                 self.dispatch(t.format_spec)
         self.write("}")
 
+    def _FormattedValue(self, t):
+        # FormattedValue(expr value, int? conversion, expr? format_spec)
+        self.write("f'''")
+        self._generic_FormattedValue(t)
+        self.write("'''")
+
     def _JoinedStr(self, t):
         # JoinedStr(expr* values)
         self.write("f'''")
         for value in t.values:
             if isinstance(value, ast.Str):
                 self.write(value.s)
+            elif isinstance(value, ast.FormattedValue):
+                self._generic_FormattedValue(value)
             else:
                 self.dispatch(value)
         self.write("'''")
diff --git a/tests/common.py b/tests/common.py
index f930308..baeba34 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -288,6 +288,13 @@ def test_raise_from(self):
     def test_bytes(self):
         self.check_roundtrip("b'123'")
 
+    @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
+    def test_formatted_value(self):
+        self.check_roundtrip('f"{value}"')
+        self.check_roundtrip('f"{value!s}"')
+        self.check_roundtrip('f"{value:4}"')
+        self.check_roundtrip('f"{value!s:4}"')
+
     @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
     def test_joined_str(self):
         self.check_roundtrip('f"{key}={value!s}"')