diff --git a/ethcore/src/engines/authority_round.rs b/ethcore/src/engines/authority_round.rs
index 023dccbfd..645642ca4 100644
--- a/ethcore/src/engines/authority_round.rs
+++ b/ethcore/src/engines/authority_round.rs
@@ -66,7 +66,7 @@ pub struct AuthorityRound {
params: CommonParams,
our_params: AuthorityRoundParams,
builtins: BTreeMap
,
- transistion_service: IoService,
+ transition_service: IoService,
message_channel: Mutex