diff --git a/README.md b/README.md
index ea11556..c404d97 100644
--- a/README.md
+++ b/README.md
@@ -121,6 +121,12 @@ Change the tracking branch of nixpkgs from unstable to 23.05:
 niv modify nixpkgs --branch nixos-23.05
 ```
 
+Add nixpkgs unstable:
+
+```shell
+niv add NixOS/nixpkgs -n unstable -b nixpkgs-unstable
+```
+
 ## Add Home Manager with niv
 
 Home Manager:
diff --git a/nix/sources.json b/nix/sources.json
index d54bd82..95ceffb 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -34,5 +34,17 @@
         "type": "tarball",
         "url": "https://github.com/NixOS/nixpkgs/archive/898cb2064b6e98b8c5499f37e81adbdf2925f7c5.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "unstable": {
+        "branch": "nixpkgs-unstable",
+        "description": "Nix Packages collection & NixOS",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "12bdeb01ff9e2d3917e6a44037ed7df6e6c3df9d",
+        "sha256": "0f17bpv8gnndri2pbylcmmg02jl8m5ypggiwlpaazn02k2wcdja5",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/12bdeb01ff9e2d3917e6a44037ed7df6e6c3df9d.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }