diff --git a/lib/Parser.js b/lib/Parser.js
index 16297d36..207b67ef 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -507,7 +507,7 @@ function parseBodyStructure(cur, literals, prefix, partID) {
       if (Array.isArray(cur[2])) {
         part.params = {};
         for (i = 0, len = cur[2].length; i < len; i += 2)
-          part.params[cur[2][i].toLowerCase()] = cur[2][i + 1];
+          part.params[cur[2][i].toLowerCase()] = decodeWords(cur[2][i + 1]);
         if (cur[1] === null)
           ++next;
       }
@@ -554,7 +554,7 @@ function parseStructExtra(part, partLen, cur, next) {
         disposition.params = {};
         for (var i = 0, len = cur[next][1].length, key; i < len; i += 2) {
           key = cur[next][1][i].toLowerCase();
-          disposition.params[key] = cur[next][1][i + 1];
+          disposition.params[key] = decodeWords(cur[next][1][i + 1]);
         }
       }
     } else if (cur[next] !== null)