diff --git a/src/decimal128.ts b/src/decimal128.ts
index f798cbf9..d3d197d6 100644
--- a/src/decimal128.ts
+++ b/src/decimal128.ts
@@ -167,11 +167,18 @@ export class Decimal128 {
 
   readonly bytes!: Buffer;
 
-  /** @param bytes - a buffer containing the raw Decimal128 bytes in little endian order */
-  constructor(bytes: Buffer) {
+  /**
+   * @param bytes - a buffer containing the raw Decimal128 bytes in little endian order,
+   *                or a string representation as returned by .toString()
+   */
+  constructor(bytes: Buffer | string) {
     if (!(this instanceof Decimal128)) return new Decimal128(bytes);
 
-    this.bytes = bytes;
+    if (typeof bytes === 'string') {
+      this.bytes = Decimal128.fromString(bytes).bytes;
+    } else {
+      this.bytes = bytes;
+    }
   }
 
   /**
@@ -796,7 +803,7 @@ export class Decimal128 {
   }
 
   inspect(): string {
-    return `Decimal128.fromString("${this.toString()}")`;
+    return `new Decimal128("${this.toString()}")`;
   }
 }
 
diff --git a/src/long.ts b/src/long.ts
index 0d059e25..977a9d39 100644
--- a/src/long.ts
+++ b/src/long.ts
@@ -97,16 +97,28 @@ export class Long {
   /**
    * Constructs a 64 bit two's-complement integer, given its low and high 32 bit values as *signed* integers.
    *  See the from* functions below for more convenient ways of constructing Longs.
+   *
+   * Acceptable signatures are:
+   * - Long(low, high, unsigned?)
+   * - Long(bigint, unsigned?)
+   * - Long(string, unsigned?)
+   *
    * @param low - The low (signed) 32 bits of the long
    * @param high - The high (signed) 32 bits of the long
    * @param unsigned - Whether unsigned or not, defaults to signed
    */
-  constructor(low = 0, high = 0, unsigned?: boolean) {
+  constructor(low: number | bigint | string = 0, high?: number | boolean, unsigned?: boolean) {
     if (!(this instanceof Long)) return new Long(low, high, unsigned);
 
-    this.low = low | 0;
-    this.high = high | 0;
-    this.unsigned = !!unsigned;
+    if (typeof low === 'bigint') {
+      Object.assign(this, Long.fromBigInt(low, !!high));
+    } else if (typeof low === 'string') {
+      Object.assign(this, Long.fromString(low, !!high));
+    } else {
+      this.low = low | 0;
+      this.high = (high as number) | 0;
+      this.unsigned = !!unsigned;
+    }
 
     Object.defineProperty(this, '__isLong__', {
       value: true,
@@ -994,7 +1006,7 @@ export class Long {
   }
 
   inspect(): string {
-    return `Long.fromString("${this.toString()}"${this.unsigned ? ', true' : ''})`;
+    return `new Long("${this.toString()}"${this.unsigned ? ', true' : ''})`;
   }
 }
 
diff --git a/test/node/bigint_tests.js b/test/node/bigint_tests.js
index b8d17bd3..32262c79 100644
--- a/test/node/bigint_tests.js
+++ b/test/node/bigint_tests.js
@@ -55,4 +55,18 @@ describe('BSON BigInt Support', function () {
     expect(() => BSON.serialize(testDoc)).to.throw(TypeError);
     // expect(() => BSON.serialize(testDoc)).to.throw();
   });
+
+  it('Should accept BigInts in Long constructor', function (done) {
+    const Long = BSON.Long;
+    expect(new Long(BigInt('0')).toString()).to.equal('0');
+    expect(new Long(BigInt('-1')).toString()).to.equal('-1');
+    expect(new Long(BigInt('-1'), true).toString()).to.equal('18446744073709551615');
+    expect(new Long(BigInt('123456789123456789')).toString()).to.equal('123456789123456789');
+    expect(new Long(BigInt('123456789123456789'), true).toString()).to.equal('123456789123456789');
+    expect(new Long(BigInt('13835058055282163712')).toString()).to.equal('-4611686018427387904');
+    expect(new Long(BigInt('13835058055282163712'), true).toString()).to.equal(
+      '13835058055282163712'
+    );
+    done();
+  });
 });
diff --git a/test/node/bson_test.js b/test/node/bson_test.js
index 56c246d9..81134994 100644
--- a/test/node/bson_test.js
+++ b/test/node/bson_test.js
@@ -2332,7 +2332,7 @@ describe('BSON', function () {
      */
     it('Decimal128', function () {
       const dec = Decimal128.fromString('1.42');
-      expect(inspect(dec)).to.equal('Decimal128.fromString("1.42")');
+      expect(inspect(dec)).to.equal('new Decimal128("1.42")');
     });
 
     /**
@@ -2356,10 +2356,10 @@ describe('BSON', function () {
      */
     it('Long', function () {
       const long = Long.fromString('42');
-      expect(inspect(long)).to.equal('Long.fromString("42")');
+      expect(inspect(long)).to.equal('new Long("42")');
 
       const unsignedLong = Long.fromString('42', true);
-      expect(inspect(unsignedLong)).to.equal('Long.fromString("42", true)');
+      expect(inspect(unsignedLong)).to.equal('new Long("42", true)');
     });
 
     /**
diff --git a/test/node/bson_types_construction_tests.js b/test/node/bson_types_construction_tests.js
index ad7507ed..fc8b1cbd 100644
--- a/test/node/bson_types_construction_tests.js
+++ b/test/node/bson_types_construction_tests.js
@@ -9,7 +9,7 @@ describe('Constructing BSON types', function () {
     new BSON.BSONSymbol('aaa');
     new BSON.Binary('aaa');
     new BSON.Code(function () {});
-    new BSON.Decimal128('aaa');
+    new BSON.Decimal128('123');
     new BSON.Double(2.3);
     new BSON.Int32(1);
     new BSON.Long(0, 0);
@@ -24,7 +24,7 @@ describe('Constructing BSON types', function () {
     BSON.BSONSymbol('aaa');
     BSON.Binary('aaa');
     BSON.Code(function () {});
-    BSON.Decimal128('aaa');
+    BSON.Decimal128('123');
     BSON.Double(2.3);
     BSON.Int32(1);
     BSON.Long(0, 0);
diff --git a/test/node/decimal128_tests.js b/test/node/decimal128_tests.js
index 38e6cf14..3ed7051f 100644
--- a/test/node/decimal128_tests.js
+++ b/test/node/decimal128_tests.js
@@ -2131,4 +2131,13 @@ describe('Decimal128', function () {
 
     done();
   });
+
+  it('accepts strings in the constructor', function (done) {
+    expect(new Decimal128('0').toString()).to.equal('0');
+    expect(new Decimal128('00').toString()).to.equal('0');
+    expect(new Decimal128('0.5').toString()).to.equal('0.5');
+    expect(new Decimal128('-0.5').toString()).to.equal('-0.5');
+    expect(new Decimal128('-1e400').toString()).to.equal('-1E+400');
+    done();
+  });
 });
diff --git a/test/node/long_tests.js b/test/node/long_tests.js
new file mode 100644
index 00000000..a1ea2e4c
--- /dev/null
+++ b/test/node/long_tests.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const BSON = require('../register-bson');
+const Long = BSON.Long;
+
+describe('Long', function () {
+  it('accepts strings in the constructor', function (done) {
+    expect(new Long('0').toString()).to.equal('0');
+    expect(new Long('00').toString()).to.equal('0');
+    expect(new Long('-1').toString()).to.equal('-1');
+    expect(new Long('-1', true).toString()).to.equal('18446744073709551615');
+    expect(new Long('123456789123456789').toString()).to.equal('123456789123456789');
+    expect(new Long('123456789123456789', true).toString()).to.equal('123456789123456789');
+    expect(new Long('13835058055282163712').toString()).to.equal('-4611686018427387904');
+    expect(new Long('13835058055282163712', true).toString()).to.equal('13835058055282163712');
+    done();
+  });
+});