diff --git a/docs/contributing/building_from_source.md b/docs/contributing/building_from_source.md
index 8b1c1ab9be..1f7bb5ac21 100644
--- a/docs/contributing/building_from_source.md
+++ b/docs/contributing/building_from_source.md
@@ -34,6 +34,15 @@ rustc -V
 cargo -V
 ```
 
+### Setup rust targets and components
+
+```shell
+rustup target add wasm32-unknown-unknown
+rustup target add wasm32-wasi
+```
+
+### Building Deno
+
 The easiest way to build Deno is by using a precompiled version of V8:
 
 ```