diff --git a/src/cjs/index.cjs b/src/cjs/index.cjs
index 7336f35..d1d11e9 100644
--- a/src/cjs/index.cjs
+++ b/src/cjs/index.cjs
@@ -88,6 +88,8 @@ function decode(buffer, offset) {
     }
     else if (first === 0xfd) {
         const val = tools.readUInt16(buffer, offset + 1, 'LE');
+        if (val < 0xfd)
+            throw new Error('non-minimal encoding');
         return {
             numberValue: val,
             bigintValue: BigInt(val),
@@ -97,6 +99,8 @@ function decode(buffer, offset) {
     }
     else if (first === 0xfe) {
         const val = tools.readUInt32(buffer, offset + 1, 'LE');
+        if (val <= 0xffff)
+            throw new Error('non-minimal encoding');
         return {
             numberValue: val,
             bigintValue: BigInt(val),
@@ -106,6 +110,8 @@ function decode(buffer, offset) {
     }
     else {
         const number = tools.readUInt64(buffer, offset + 1, 'LE');
+        if (number <= 0xffffffffn)
+            throw new Error('non-minimal encoding');
         return { numberValue: number <= Number.MAX_SAFE_INTEGER ? Number(number) : null, bigintValue: number, bytes: 9 };
     }
 }
diff --git a/src/esm/index.js b/src/esm/index.js
index ec06d97..0fddd4b 100644
--- a/src/esm/index.js
+++ b/src/esm/index.js
@@ -61,6 +61,8 @@ export function decode(buffer, offset) {
     }
     else if (first === 0xfd) {
         const val = tools.readUInt16(buffer, offset + 1, 'LE');
+        if (val < 0xfd)
+            throw new Error('non-minimal encoding');
         return {
             numberValue: val,
             bigintValue: BigInt(val),
@@ -70,6 +72,8 @@ export function decode(buffer, offset) {
     }
     else if (first === 0xfe) {
         const val = tools.readUInt32(buffer, offset + 1, 'LE');
+        if (val <= 0xffff)
+            throw new Error('non-minimal encoding');
         return {
             numberValue: val,
             bigintValue: BigInt(val),
@@ -79,6 +83,8 @@ export function decode(buffer, offset) {
     }
     else {
         const number = tools.readUInt64(buffer, offset + 1, 'LE');
+        if (number <= 0xffffffffn)
+            throw new Error('non-minimal encoding');
         return { numberValue: number <= Number.MAX_SAFE_INTEGER ? Number(number) : null, bigintValue: number, bytes: 9 };
     }
 }
diff --git a/test/index.js b/test/index.js
index bb8582d..90a00a5 100644
--- a/test/index.js
+++ b/test/index.js
@@ -102,6 +102,19 @@ tape("decode", function (t) {
         t.end();
     });
 
+    t.test("should reject a non-minimal encoding", function (t) {
+        t.throws(function () {
+            decode(Buffer.from("fd0100", "hex"));
+        }, new Error("non-minimal encoding"));
+        t.throws(function () {
+            decode(Buffer.from("fe01000000", "hex"));
+        }, new Error("non-minimal encoding"));
+        t.throws(function () {
+            decode(Buffer.from("ff0100000000000000", "hex"));
+        }, new Error("non-minimal encoding"));
+        t.end();
+    });
+
     t.test("should return null if a number is invalid", function (t) {
         var buffer = Buffer.alloc(18);
         buffer.writeUIntBE(0xff, 0, 1);
diff --git a/ts_src/index.ts b/ts_src/index.ts
index 686a076..c3d88e1 100644
--- a/ts_src/index.ts
+++ b/ts_src/index.ts
@@ -77,6 +77,7 @@ export function decode (
     // 16 bit
   } else if (first === 0xfd) {
     const val = tools.readUInt16(buffer, offset + 1, 'LE')
+    if (val < 0xfd) throw new Error('non-minimal encoding')
     return {
       numberValue: val,
       bigintValue: BigInt(val),
@@ -86,6 +87,7 @@ export function decode (
     // 32 bit
   } else if (first === 0xfe) {
     const val = tools.readUInt32(buffer, offset + 1, 'LE')
+    if (val <= 0xffff) throw new Error('non-minimal encoding')
     return {
       numberValue: val,
       bigintValue: BigInt(val),
@@ -95,6 +97,7 @@ export function decode (
     // 64 bit
   } else {
     const number = tools.readUInt64(buffer, offset + 1, 'LE')
+    if (number <= 0xffffffffn) throw new Error('non-minimal encoding')
 
     return { numberValue: number <= Number.MAX_SAFE_INTEGER ? Number(number) : null, bigintValue: number, bytes: 9 }
   }