diff --git a/doc/INSTALL.md b/doc/INSTALL.md
index 77fc52e18..9f91db72e 100644
--- a/doc/INSTALL.md
+++ b/doc/INSTALL.md
@@ -31,6 +31,7 @@ OS version: Ubuntu 15.10 or above
 
 Get dependencies:
 
+    sudo apt-get update
     sudo apt-get install -y \
       autoconf automake build-essential git libtool libgmp-dev \
       libsqlite3-dev python python3 net-tools libsodium-dev