diff --git a/src/index.js b/src/index.js
index 8d66608..c6dfd5e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -708,7 +708,7 @@ export default class ReactTable extends Methods(Lifecycle(Component)) {
       const trGroupProps = getTrGroupProps(finalState, undefined, undefined, this)
       const trProps = _.splitProps(getTrProps(finalState, undefined, undefined, this))
       return (
-        <TrGroupComponent key={i} {...trGroupProps}>
+        <TrGroupComponent key={`pad-${i}`} {...trGroupProps}>
           <TrComponent
             className={classnames(
               '-padRow',