diff --git a/ethers-contract/src/event.rs b/ethers-contract/src/event.rs
index e013b461..38d8bb3d 100644
--- a/ethers-contract/src/event.rs
+++ b/ethers-contract/src/event.rs
@@ -9,7 +9,7 @@ use std::borrow::Cow;
 use std::marker::PhantomData;
 
 /// A trait for implementing event bindings
-pub trait EthEvent: Detokenize {
+pub trait EthEvent: Detokenize + Send + Sync {
     /// The name of the event this type represents
     fn name() -> Cow<'static, str>;
 
diff --git a/ethers-contract/src/log.rs b/ethers-contract/src/log.rs
index bfc54d53..cb538649 100644
--- a/ethers-contract/src/log.rs
+++ b/ethers-contract/src/log.rs
@@ -3,7 +3,7 @@ use ethers_core::abi::Error;
 use ethers_core::abi::RawLog;
 
 /// A trait for types (events) that can be decoded from a `RawLog`
-pub trait EthLogDecode {
+pub trait EthLogDecode: Send + Sync {
     /// decode from a `RawLog`
     fn decode_log(log: &RawLog) -> Result<Self, Error>
     where
diff --git a/ethers-contract/src/stream.rs b/ethers-contract/src/stream.rs
index c8671902..b0385b0a 100644
--- a/ethers-contract/src/stream.rs
+++ b/ethers-contract/src/stream.rs
@@ -4,7 +4,7 @@ use pin_project::pin_project;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
-type MapEvent<'a, R, E> = Box<dyn Fn(Log) -> Result<R, E> + 'a>;
+type MapEvent<'a, R, E> = Box<dyn Fn(Log) -> Result<R, E> + 'a + Send + Sync>;
 
 #[pin_project]
 /// Generic wrapper around Log streams, mapping their content to a specific