diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,9 @@
 # Revision history for network-control
 
+## 0.1.6
+
+* Allowing size 0.
+
 ## 0.1.5
 
 * New API: `lookup'` adjusts the target priority.
diff --git a/Network/Control/LRUCache.hs b/Network/Control/LRUCache.hs
--- a/Network/Control/LRUCache.hs
+++ b/Network/Control/LRUCache.hs
@@ -46,14 +46,12 @@
     :: Int
     -- ^ The size of 'LRUCache'.
     -> LRUCache k v
-empty capacity
-    | capacity < 1 = error "LRUCache.empty: capacity < 1"
-    | otherwise =
-        LRUCache
-            { lcLimit = capacity
-            , lcTick = 0
-            , lcQueue = PSQ.empty
-            }
+empty capacity =
+    LRUCache
+        { lcLimit = capacity
+        , lcTick = 0
+        , lcQueue = PSQ.empty
+        }
 
 -- | Empty 'LRUCache'. /O(1)/
 empty'
diff --git a/network-control.cabal b/network-control.cabal
--- a/network-control.cabal
+++ b/network-control.cabal
@@ -1,6 +1,6 @@
 cabal-version:   3.0
 name:            network-control
-version:         0.1.5
+version:         0.1.6
 license:         BSD-3-Clause
 license-file:    LICENSE
 maintainer:      kazu@iij.ad.jp