diff --git a/guide/src/qs_4_5.md b/guide/src/qs_4_5.md
index dcdea3fe5..5a11af733 100644
--- a/guide/src/qs_4_5.md
+++ b/guide/src/qs_4_5.md
@@ -134,3 +134,18 @@ fn index(req: HttpRequest) -> Result<&'static str> {
 ```
 
 In this example *BAD REQUEST* response get generated for `MyError` error.
+
+## Error logging
+
+Actix logs all errors with `WARN` log level. If log level set to `DEBUG`
+and `RUST_BACKTRACE` is enabled, backtrace get logged. The Error type uses
+cause's error backtrace if available, if the underlying failure does not provide
+a backtrace, a new backtrace is constructed pointing to that conversion point
+(rather than the origin of the error). This construction only happens if there
+is no underlying backtrace; if it does have a backtrace no new backtrace is constructed.
+
+You can enable backtrace and debug logging with following command: 
+
+```
+>> RUST_BACKTRACE=1 RUST_LOG=actix_web=debug cargo run
+```