diff --git a/README.md b/README.md
index 744d47c..9010213 100644
--- a/README.md
+++ b/README.md
@@ -150,6 +150,10 @@ enabled using the `-cache` flag.  It supports the following values:
    available memory and is not recommended for production systems)
  - directory on local disk (e.g. `/tmp/imageproxy`) - will cache images
    on disk, limited to the size specified in the `-cacheSize` flag.
+ - s3 URL (e.g. `s3://s3-us-west-2.amazonaws.com/my-bucket`) - will cache
+   images on Amazon S3.  This requires either an IAM role and instance profile
+   with access to your your bucket or `AWS_ACCESS_KEY_ID` and `AWS_SECRET_KEY`
+   environmental parameters set.
 
 For example, to cache files on disk, allowing up to 100MB of space:
 
diff --git a/cmd/imageproxy/main.go b/cmd/imageproxy/main.go
index ec7ff29..14fa7cc 100644
--- a/cmd/imageproxy/main.go
+++ b/cmd/imageproxy/main.go
@@ -27,6 +27,7 @@ import (
 	"github.com/gregjones/httpcache"
 	"github.com/gregjones/httpcache/diskcache"
 	"github.com/peterbourgon/diskv"
+	"sourcegraph.com/sourcegraph/s3cache"
 	"willnorris.com/go/imageproxy"
 )
 
@@ -120,6 +121,9 @@ func parseCache() (imageproxy.Cache, error) {
 	}
 
 	switch u.Scheme {
+	case "s3":
+		u.Scheme = "https"
+		return s3cache.New(u.String()), nil
 	case "file":
 		fallthrough
 	default: