diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e0dd95046..499efa3850 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 1.17.0-beta.x
+
+- Fix `ElectionSize` type (Thanks to https://github.com/arjanz)
+
 # 1.16.1 May 26, 2020
 
 - Support for Polkadot CC1 types & signed extensions
diff --git a/packages/types/src/interfaces/staking/definitions.ts b/packages/types/src/interfaces/staking/definitions.ts
index 49e48592c8..51d50e96de 100644
--- a/packages/types/src/interfaces/staking/definitions.ts
+++ b/packages/types/src/interfaces/staking/definitions.ts
@@ -52,8 +52,8 @@ export default {
       exposures: 'Vec<(AccountId, Exposure)>'
     },
     ElectionSize: {
-      validators: 'ValidatorIndex',
-      nominators: 'NominatorIndex'
+      validators: 'Compact<ValidatorIndex>',
+      nominators: 'Compact<NominatorIndex>'
     },
     ElectionStatus: {
       _enum: {