diff --git a/.changeset/cuddly-coins-carry.md b/.changeset/cuddly-coins-carry.md
new file mode 100644
index 0000000000..0511d75013
--- /dev/null
+++ b/.changeset/cuddly-coins-carry.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added REI Mainnet.
diff --git a/src/chains/definitions/rei.ts b/src/chains/definitions/rei.ts
new file mode 100644
index 0000000000..b35ec334b2
--- /dev/null
+++ b/src/chains/definitions/rei.ts
@@ -0,0 +1,24 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const rei = /*#__PURE__*/ defineChain({
+  id: 47805,
+  name: 'REI Mainnet',
+  nativeCurrency: {
+    decimals: 18,
+    name: 'REI',
+    symbol: 'REI',
+  },
+  rpcUrls: {
+    default: { 
+      http: ['https://rpc.rei.network'],
+      webSocket: ['wss://rpc.rei.network'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'REI Scan',
+      url: 'https://scan.rei.network',
+    },
+  },
+  testnet: false,
+})
diff --git a/src/chains/index.ts b/src/chains/index.ts
index 4c06700bab..94706db9b7 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -321,6 +321,7 @@ export { qTestnet } from './definitions/qTestnet.js'
 export { real } from './definitions/real.js'
 export { redbellyTestnet } from './definitions/redbellyTestnet.js'
 export { redstone } from './definitions/redstone.js'
+export { rei } from './definitions/rei.js'
 export { reyaNetwork } from './definitions/reyaNetwork.js'
 export { rollux } from './definitions/rollux.js'
 export { rolluxTestnet } from './definitions/rolluxTestnet.js'