diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9427f52..9f90c4f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [1.1.0] - 2018-11-13
 ### Changed
 - Update `github.com/cybozu-go/cmd` to `github.com/cybozu-go/well` (#7, #9).
 - Replace TravisCI with CircleCI.
@@ -20,5 +21,6 @@ All notable changes to this project will be documented in this file.
 
 [cmd]: https://github.com/cybozu-go/cmd
 [spec]: https://github.com/cybozu-go/cmd/blob/master/README.md#specifications
-[Unreleased]: https://github.com/cybozu-go/transocks/compare/v1.0.0...HEAD
+[Unreleased]: https://github.com/cybozu-go/transocks/compare/v1.1.0...HEAD
+[1.1.0]: https://github.com/cybozu-go/transocks/compare/v1.0.0...v1.1.0
 [1.0.0]: https://github.com/cybozu-go/transocks/compare/v0.1...v1.0.0
diff --git a/RELEASE.md b/RELEASE.md
new file mode 100644
index 0000000..40d048d
--- /dev/null
+++ b/RELEASE.md
@@ -0,0 +1,54 @@
+Release procedure
+=================
+
+This document describes how to release a new version of coil.
+
+Versioning
+----------
+
+Follow [semantic versioning 2.0.0][semver] to choose the new version number.
+
+Prepare change log entries
+--------------------------
+
+Add notable changes since the last release to [CHANGELOG.md](CHANGELOG.md).
+It should look like:
+
+```markdown
+(snip)
+## [Unreleased]
+
+### Added
+- Implement ... (#35)
+
+### Changed
+- Fix a bug in ... (#33)
+
+### Removed
+- Deprecated `-option` is removed ... (#39)
+
+(snip)
+```
+
+Bump version
+------------
+
+1. Determine a new version number.  Let it write `$VERSION`.
+1. Checkout `master` branch.
+1. Edit `CHANGELOG.md` for the new version ([example][]).
+1. Commit the change and add a git tag, then push them.
+
+    ```console
+    $ git commit -a -m "Bump version to $VERSION"
+    $ git tag v$VERSION
+    $ git push origin master --tags
+    ```
+
+Publish GitHub release page
+---------------------------
+
+Go to https://github.com/cybozu-go/coil/releases and edit the tag.
+Finally, press `Publish release` button.
+
+[semver]: https://semver.org/spec/v2.0.0.html
+[example]: https://github.com/cybozu-go/etcdpasswd/commit/77d95384ac6c97e7f48281eaf23cb94f68867f79