diff --git a/.appveyor.yml b/.appveyor.yml
index a2e7383864..adbcfac556 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -13,6 +13,7 @@ environment:
   MTIME_CACHE_DB: $(APPVEYOR_BUILD_FOLDER)\mtime_cache.xml
   CARGO_HOME: $(USERPROFILE)\.cargo
   RUSTUP_HOME: $(USERPROFILE)\.rustup
+  RUST_BACKTRACE: 1
   RELEASE_ARTIFACT: deno_win_x64.zip
 
   # Appveyor uses 7zip to pack cache directories. We use these options:
diff --git a/.travis.yml b/.travis.yml
index 7912c7a9e0..e90e3ebe48 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,7 @@ env:
   global:
   - CARGO_HOME=$HOME/.cargo/
   - RUSTUP_HOME=$HOME/.rustup/
+  - RUST_BACKTRACE=1
   - HOMEBREW_PATH=$HOME/homebrew/
   - DENO_BUILD_ARGS="use_custom_libcxx=false use_sysroot=false"
   - DENO_BUILD_PATH=$HOME/out/Default