diff --git a/packages/api-codec/src/Header.ts b/packages/api-codec/src/Header.ts
index 5e3c4307bd45..1082bc59fb93 100644
--- a/packages/api-codec/src/Header.ts
+++ b/packages/api-codec/src/Header.ts
@@ -6,7 +6,7 @@ import BN from 'bn.js';
 import blake2Asu8a from '@polkadot/util-crypto/blake2/asU8a';
 
 import Bytes from './codec/Bytes';
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 import Struct from './codec/Struct';
 import Vector from './codec/Vector';
 
@@ -20,7 +20,7 @@ type DigestStruct = {
 type HeaderStruct = {
   digest?: DigestStruct,
   extrinsicsRoot?: Hash | Uint8Array | string,
-  number?: Long | BN | number | string,
+  number?: UInt | BN | number | string,
   parentHash?: Hash | Uint8Array | string,
   stateRoot?: Hash | Uint8Array | string
 };
diff --git a/packages/api-codec/src/U128.ts b/packages/api-codec/src/U128.ts
index ac1708999d1d..3720ff935e10 100644
--- a/packages/api-codec/src/U128.ts
+++ b/packages/api-codec/src/U128.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U128 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U128 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 128);
   }
 }
diff --git a/packages/api-codec/src/U16.ts b/packages/api-codec/src/U16.ts
index 7b401f597277..a64cbdf28715 100644
--- a/packages/api-codec/src/U16.ts
+++ b/packages/api-codec/src/U16.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U16 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U16 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 16);
   }
 }
diff --git a/packages/api-codec/src/U256.ts b/packages/api-codec/src/U256.ts
index 4ddf61933431..6edcaefac973 100644
--- a/packages/api-codec/src/U256.ts
+++ b/packages/api-codec/src/U256.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U256 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U256 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 256);
   }
 }
diff --git a/packages/api-codec/src/U32.ts b/packages/api-codec/src/U32.ts
index 362e4d02f4ea..2f1453b1a23e 100644
--- a/packages/api-codec/src/U32.ts
+++ b/packages/api-codec/src/U32.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U32 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U32 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 32);
   }
 }
diff --git a/packages/api-codec/src/U64.ts b/packages/api-codec/src/U64.ts
index aa20d9a3e535..56770ca2f620 100644
--- a/packages/api-codec/src/U64.ts
+++ b/packages/api-codec/src/U64.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U64 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U64 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 64);
   }
 }
diff --git a/packages/api-codec/src/U8.ts b/packages/api-codec/src/U8.ts
index d0b75b5d3648..0860b5e4b6f4 100644
--- a/packages/api-codec/src/U8.ts
+++ b/packages/api-codec/src/U8.ts
@@ -4,10 +4,10 @@
 
 import BN from 'bn.js';
 
-import Long from './codec/Long';
+import UInt from './codec/UInt';
 
-export default class U8 extends Long {
-  constructor (value?: Long | BN | string | number) {
+export default class U8 extends UInt {
+  constructor (value?: UInt | BN | string | number) {
     super(value, 8);
   }
 }
diff --git a/packages/api-codec/src/codec/Long.ts b/packages/api-codec/src/codec/UInt.ts
similarity index 84%
rename from packages/api-codec/src/codec/Long.ts
rename to packages/api-codec/src/codec/UInt.ts
index 9c479fa250b8..06de236be28e 100644
--- a/packages/api-codec/src/codec/Long.ts
+++ b/packages/api-codec/src/codec/UInt.ts
@@ -21,19 +21,19 @@ type BitLength = 8 | 16 | 32 | 64 | 128 | 256;
 //
 // TODO:
 //   - Apart from encoding/decoding we don't actuall keep check on the sizes, is this good enough?
-export default class Long extends Base<BN> {
+export default class UInt extends Base<BN> {
   private _bitLength: BitLength;
 
-  constructor (value: Long | BN | string | number = 0, bitLength: BitLength = 64) {
+  constructor (value: UInt | BN | string | number = 0, bitLength: BitLength = 64) {
     super(
-      Long.decode(value)
+      UInt.decode(value)
     );
 
     this._bitLength = bitLength;
   }
 
-  static decode (value: Long | BN | string | number): BN {
-    if (value instanceof Long) {
+  static decode (value: UInt | BN | string | number): BN {
+    if (value instanceof UInt) {
       return value.raw;
     } else if (isHex(value)) {
       return hexToBn(value as string);
@@ -48,13 +48,13 @@ export default class Long extends Base<BN> {
     return this._bitLength / 8;
   }
 
-  fromJSON (input: any): Long {
-    this.raw = Long.decode(input);
+  fromJSON (input: any): UInt {
+    this.raw = UInt.decode(input);
 
     return this;
   }
 
-  fromU8a (input: Uint8Array): Long {
+  fromU8a (input: Uint8Array): UInt {
     this.raw = u8aToBn(input.subarray(0, this.byteLength()), true);
 
     return this;