diff --git a/ethcore/src/block_queue.rs b/ethcore/src/block_queue.rs
index 0f5985f06..879798868 100644
--- a/ethcore/src/block_queue.rs
+++ b/ethcore/src/block_queue.rs
@@ -30,6 +30,9 @@ use util::panics::*;
 
 known_heap_size!(0, UnVerifiedBlock, VerifyingBlock, PreVerifiedBlock);
 
+const MIN_MEM_LIMIT: usize = 16384;
+const MIN_QUEUE_LIMIT: usize = 512;
+
 /// Block queue configuration
 #[derive(Debug)]
 pub struct BlockQueueConfig {
@@ -178,8 +181,8 @@ impl BlockQueue {
 			deleting: deleting.clone(),
 			processing: RwLock::new(HashSet::new()),
 			empty: empty.clone(),
-			max_queue_size: config.max_queue_size,
-			max_mem_use: config.max_mem_use,
+			max_queue_size: max(config.max_queue_size, MIN_QUEUE_LIMIT),
+			max_mem_use: max(config.max_mem_use, MIN_MEM_LIMIT),
 		}
 	}
 
@@ -480,4 +483,19 @@ mod tests {
 
 		assert!(queue.queue_info().is_empty());
 	}
+
+	#[test]
+	fn test_mem_limit() {
+		let spec = get_test_spec();
+		let engine = spec.to_engine().unwrap();
+		let mut config = BlockQueueConfig::default();
+		config.max_mem_use = super::MIN_MEM_LIMIT;  // empty queue uses about 15000
+		let mut queue = BlockQueue::new(config, Arc::new(engine), IoChannel::disconnected());
+		assert!(!queue.queue_info().is_full());
+		let mut blocks = get_good_dummy_block_seq(50);
+		for b in blocks.drain(..) {
+			queue.import_block(b).unwrap();
+		}
+		assert!(queue.queue_info().is_full());
+	}
 }
diff --git a/ethcore/src/tests/helpers.rs b/ethcore/src/tests/helpers.rs
index 510833f4d..808d2e5fb 100644
--- a/ethcore/src/tests/helpers.rs
+++ b/ethcore/src/tests/helpers.rs
@@ -253,6 +253,25 @@ pub fn get_temp_state_in(path: &Path) -> State {
 	State::new(journal_db, U256::from(0u8))
 }
 
+pub fn get_good_dummy_block_seq(count: usize) -> Vec<Bytes> {
+	let test_spec = get_test_spec();
+	let test_engine = test_spec.to_engine().unwrap();
+	let mut parent = test_engine.spec().genesis_header().hash();
+	let mut r = Vec::new();
+	for i in 1 .. count + 1 {
+		let mut block_header = Header::new();
+		block_header.gas_limit = decode(test_engine.spec().engine_params.get("minGasLimit").unwrap());
+		block_header.difficulty = decode(test_engine.spec().engine_params.get("minimumDifficulty").unwrap());
+		block_header.timestamp = i as u64;
+		block_header.number = i as u64;
+		block_header.parent_hash = parent;
+		block_header.state_root = test_engine.spec().genesis_header().state_root;
+		parent = block_header.hash();
+		r.push(create_test_block(&block_header));
+	}
+	r
+}
+
 pub fn get_good_dummy_block() -> Bytes {
 	let mut block_header = Header::new();
 	let test_spec = get_test_spec();