diff --git a/web3.js/module.flow.js b/web3.js/module.flow.js
index 2f81acbbc2..8bb19c3ca6 100644
--- a/web3.js/module.flow.js
+++ b/web3.js/module.flow.js
@@ -220,6 +220,14 @@ declare module '@solana/web3.js' {
       amount: number,
     ): Transaction;
     static assign(from: PublicKey, programId: PublicKey): Transaction;
+    static createAccountWithSeed(
+      from: PublicKey,
+      newAccount: PublicKey,
+      seed: string,
+      lamports: number,
+      space: number,
+      programId: PublicKey,
+    ): Transaction;
   }
 
   // === src/validator-info.js ===
diff --git a/web3.js/src/layout.js b/web3.js/src/layout.js
index 6c3e06b709..667b4ca7ca 100644
--- a/web3.js/src/layout.js
+++ b/web3.js/src/layout.js
@@ -43,5 +43,25 @@ export const rustString = (property: string = 'string') => {
     return _encode(data, buffer, offset);
   };
 
+  rsl.alloc = str => {
+    return (
+      BufferLayout.u32().span +
+      BufferLayout.u32().span +
+      Buffer.from(str, 'utf8').length
+    );
+  };
+
   return rsl;
 };
+
+export function getAlloc(type: Object, fields: Object): number {
+  let alloc = 0;
+  type.layout.fields.forEach(item => {
+    if (item.span >= 0) {
+      alloc += item.span;
+    } else if (typeof item.alloc === 'function') {
+      alloc += item.alloc(fields[item.property]);
+    }
+  });
+  return alloc;
+}
diff --git a/web3.js/src/system-program.js b/web3.js/src/system-program.js
index e1b923b8bb..fad0fcdd2c 100644
--- a/web3.js/src/system-program.js
+++ b/web3.js/src/system-program.js
@@ -66,6 +66,7 @@ export class SystemInstruction extends TransactionInstruction {
   get fromPublicKey(): PublicKey | null {
     if (
       this.type == SystemInstructionLayout.Create ||
+      this.type == SystemInstructionLayout.CreateWithSeed ||
       this.type == SystemInstructionLayout.Transfer
     ) {
       return this.keys[0].pubkey;
@@ -80,6 +81,7 @@ export class SystemInstruction extends TransactionInstruction {
   get toPublicKey(): PublicKey | null {
     if (
       this.type == SystemInstructionLayout.Create ||
+      this.type == SystemInstructionLayout.CreateWithSeed ||
       this.type == SystemInstructionLayout.Transfer
     ) {
       return this.keys[1].pubkey;
@@ -95,7 +97,10 @@ export class SystemInstruction extends TransactionInstruction {
     const data = this.type.layout.decode(this.data);
     if (this.type == SystemInstructionLayout.Transfer) {
       return data.amount;
-    } else if (this.type == SystemInstructionLayout.Create) {
+    } else if (
+      this.type == SystemInstructionLayout.Create ||
+      this.type == SystemInstructionLayout.CreateWithSeed
+    ) {
       return data.lamports;
     }
     return null;
@@ -139,13 +144,25 @@ const SystemInstructionLayout = Object.freeze({
       BufferLayout.ns64('amount'),
     ]),
   },
+  CreateWithSeed: {
+    index: 3,
+    layout: BufferLayout.struct([
+      BufferLayout.u32('instruction'),
+      Layout.rustString('seed'),
+      BufferLayout.ns64('lamports'),
+      BufferLayout.ns64('space'),
+      Layout.publicKey('programId'),
+    ]),
+  },
 });
 
 /**
  * Populate a buffer of instruction data using the SystemInstructionType
  */
 function encodeData(type: SystemInstructionType, fields: Object): Buffer {
-  const data = Buffer.alloc(type.layout.span);
+  const allocLength =
+    type.layout.span >= 0 ? type.layout.span : Layout.getAlloc(type, fields);
+  const data = Buffer.alloc(allocLength);
   const layoutFields = Object.assign({instruction: type.index}, fields);
   type.layout.encode(layoutFields, data);
   return data;
@@ -221,4 +238,34 @@ export class SystemProgram {
       data,
     });
   }
+
+  /**
+   * Generate a Transaction that creates a new account at
+   *   an address generated with `from`, a seed, and programId
+   */
+  static createAccountWithSeed(
+    from: PublicKey,
+    newAccount: PublicKey,
+    seed: string,
+    lamports: number,
+    space: number,
+    programId: PublicKey,
+  ): Transaction {
+    const type = SystemInstructionLayout.CreateWithSeed;
+    const data = encodeData(type, {
+      seed,
+      lamports,
+      space,
+      programId: programId.toBuffer(),
+    });
+
+    return new Transaction().add({
+      keys: [
+        {pubkey: from, isSigner: true, isWritable: true},
+        {pubkey: newAccount, isSigner: false, isWritable: true},
+      ],
+      programId: SystemProgram.programId,
+      data,
+    });
+  }
 }
diff --git a/web3.js/test/system-program.test.js b/web3.js/test/system-program.test.js
index 8965628dd3..c690b68782 100644
--- a/web3.js/test/system-program.test.js
+++ b/web3.js/test/system-program.test.js
@@ -50,6 +50,25 @@ test('assign', () => {
   // TODO: Validate transaction contents more
 });
 
+test('createAccountWithSeed', () => {
+  const from = new Account();
+  const newAccount = new Account();
+  let transaction;
+
+  transaction = SystemProgram.createAccountWithSeed(
+    from.publicKey,
+    newAccount.publicKey,
+    'hi there',
+    123,
+    BudgetProgram.space,
+    BudgetProgram.programId,
+  );
+
+  expect(transaction.keys).toHaveLength(2);
+  expect(transaction.programId).toEqual(SystemProgram.programId);
+  // TODO: Validate transaction contents more
+});
+
 test('SystemInstruction create', () => {
   const from = new Account();
   const to = new Account();
@@ -104,6 +123,30 @@ test('SystemInstruction assign', () => {
   expect(systemInstruction.programId).toEqual(SystemProgram.programId);
 });
 
+test('SystemInstruction createWithSeed', () => {
+  const from = new Account();
+  const to = new Account();
+  const program = new Account();
+  const amount = 42;
+  const space = 100;
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const create = SystemProgram.createAccountWithSeed(
+    from.publicKey,
+    to.publicKey,
+    'hi there',
+    amount,
+    space,
+    program.publicKey,
+  );
+  const transaction = new Transaction({recentBlockhash}).add(create);
+
+  const systemInstruction = SystemInstruction.from(transaction.instructions[0]);
+  expect(systemInstruction.fromPublicKey).toEqual(from.publicKey);
+  expect(systemInstruction.toPublicKey).toEqual(to.publicKey);
+  expect(systemInstruction.amount).toEqual(amount);
+  expect(systemInstruction.programId).toEqual(SystemProgram.programId);
+});
+
 test('non-SystemInstruction error', () => {
   const from = new Account();
   const program = new Account();