diff --git a/ethcore/src/client.rs b/ethcore/src/client.rs
index 268d99229..bf6f4bd71 100644
--- a/ethcore/src/client.rs
+++ b/ethcore/src/client.rs
@@ -268,7 +268,7 @@ impl Client {
 		// Check the block isn't so old we won't be able to enact it.
 		let best_block_number = self.chain.read().unwrap().best_block_number();
 		debug!("Best: {}, importing: {}", best_block_number, header.number());
-		if header.number() <= best_block_number - HISTORY {
+		if best_block_number >= HISTORY && header.number() <= best_block_number - HISTORY {
 			warn!(target: "client", "Block import failed for #{} ({})\nBlock is ancient (current best block: #{}).", header.number(), header.hash(), best_block_number);
 			return Err(());
 		}