diff --git a/eth/main.cpp b/eth/main.cpp
index 04e4871b3..993451378 100644
--- a/eth/main.cpp
+++ b/eth/main.cpp
@@ -236,7 +236,7 @@ int main(int argc, char** argv)
 				c.stopMining();
 			else
 				c.startMining();
-			usleep(100000);
+			std::this_thread::sleep_for(std::chrono::microseconds(100000));
 		}
 	}
 
diff --git a/libethereum/Client.cpp b/libethereum/Client.cpp
index ea9c6b3bc..df3cc7e18 100644
--- a/libethereum/Client.cpp
+++ b/libethereum/Client.cpp
@@ -64,7 +64,7 @@ Client::~Client()
 	if (m_workState == Active)
 		m_workState = Deleting;
 	while (m_workState != Deleted)
-		usleep(10000);
+		std::this_thread::sleep_for(std::chrono::microseconds(10000));
 }
 
 void Client::startNetwork(short _listenPort, std::string const& _seedHost, short _port, NodeMode _mode, unsigned _peers, string const& _publicIP, bool _upnp)
@@ -158,7 +158,7 @@ void Client::work()
 		}
 	}
 	else
-		usleep(100000);
+		std::this_thread::sleep_for(std::chrono::microseconds(100000));
 }
 
 void Client::lock()
diff --git a/libethereum/PeerNetwork.cpp b/libethereum/PeerNetwork.cpp
index ecc2e6f72..089cc29cb 100644
--- a/libethereum/PeerNetwork.cpp
+++ b/libethereum/PeerNetwork.cpp
@@ -919,7 +919,7 @@ bool PeerServer::process(BlockChain& _bc, TransactionQueue& _tq, Overlay& _o)
 std::vector<PeerInfo> PeerServer::peers() const
 {
 	const_cast<PeerServer*>(this)->pingAll();
-	usleep(200000);
+	std::this_thread::sleep_for(std::chrono::microseconds(200000));
 	std::vector<PeerInfo> ret;
 	for (auto& i: m_peers)
 		if (auto j = i.lock())
diff --git a/libethereum/UPnP.cpp b/libethereum/UPnP.cpp
index 5b92d5373..c70177421 100644
--- a/libethereum/UPnP.cpp
+++ b/libethereum/UPnP.cpp
@@ -117,7 +117,7 @@ int UPnP::addRedirect(char const* addr, int port)
 	// Failed - now try (random external, port internal) and cycle up to 10 times.
 	for (uint i = 0; i < 10; ++i)
 	{
-		port = random() % 65535 - 1024 + 1024;
+		port = rand() % 65535 - 1024 + 1024;
 		sprintf(port_str, "%d", port);
 		if (!UPNP_AddPortMapping(m_urls->controlURL, m_data->first.servicetype, NULL, port_str, addr, "ethereum", "TCP", NULL, NULL))
 			return port;
diff --git a/test/peer.cpp b/test/peer.cpp
index 5a440a88f..6a5fb610a 100644
--- a/test/peer.cpp
+++ b/test/peer.cpp
@@ -53,7 +53,7 @@ int peerTest(int argc, char** argv)
 
 	for (int i = 0; ; ++i)
 	{
-		usleep(100000);
+		std::this_thread::sleep_for(std::chrono::microseconds(100000));
 		pn.process(ch);
 		if (!(i % 10))
 			pn.pingAll();