diff --git a/ride/multisig.ride b/ride/multisig.ride
index e7d4c63f..5bdad0e2 100644
--- a/ride/multisig.ride
+++ b/ride/multisig.ride
@@ -32,16 +32,24 @@ func validatePublicKey(publicKey: String) = {
   fromBase58String(publicKey).size() == publicKeySize
 }
 
+func validateOwner(owners: List[String], pk: String) = {
+  strict checks = [
+    validatePublicKey(pk) || throwErr("invalid owner public key"),
+    owners.indexOf(pk) == owners.lastIndexOf(pk) || throwErr("must not contain duplicates")
+  ]
+
+  owners
+}
+
 @Callable(i)
 func init(owners: List[String], quorum: Int) = {
-  func validateOwner(acc: Unit, pk: String) = validatePublicKey(pk) || throwErr("invalid owner public key")
   strict checks = [
     i.caller == this || throwErr("init: not allowed"),
     !getString(kMultisig).isDefined() || throwErr("init: already initialized"),
     (owners.size() > 0 && owners.size() <= maxOwners) || throwErr("init: invalid owners"),
     (quorum > 0 && quorum <= owners.size()) || throwErr("init: invalid quorum"),
     # maxOwners
-    FOLD<10>(owners, unit, validateOwner)
+    FOLD<10>(owners, owners, validateOwner)
   ]
 
   ([
diff --git a/test/components/multisig/init.spec.mjs b/test/components/multisig/init.spec.mjs
index ca68a384..839686f4 100644
--- a/test/components/multisig/init.spec.mjs
+++ b/test/components/multisig/init.spec.mjs
@@ -29,7 +29,7 @@ describe(`[${process.pid}] multisig: init`, () => {
     })).to.be.rejectedWith('not allowed');
   });
 
-  it('invalid owners', async () => {
+  it('should throw if owners size <= 0', async () => {
     const owners = [];
     const quorum = 0;
 
@@ -42,6 +42,38 @@ describe(`[${process.pid}] multisig: init`, () => {
     })).to.be.rejectedWith('invalid owners');
   });
 
+  it('should throw if owners size > maxOwners', async () => {
+    const maxOwners = 10;
+    const owners = Array(maxOwners + 1).fill(accounts.admin0.publicKey);
+    const quorum = 0;
+
+    return expect(init({
+      dApp: accounts.multisig.address,
+      caller: accounts.multisig.seed,
+      owners,
+      quorum,
+      additionalFee: 4e5,
+    })).to.be.rejectedWith('invalid owners');
+  });
+
+  it('should throw id there are duplicates in owners', async () => {
+    const owners = [
+      accounts.admin0.publicKey,
+      accounts.admin1.publicKey,
+      accounts.admin1.publicKey,
+      accounts.admin2.publicKey,
+    ];
+    const quorum = 3;
+
+    return expect(init({
+      dApp: accounts.multisig.address,
+      caller: accounts.multisig.seed,
+      owners,
+      quorum,
+      additionalFee: 4e5,
+    })).to.be.rejectedWith('must not contain duplicates');
+  });
+
   it('invalid quorum', async () => {
     const owners = [accounts.admin0.publicKey];
     const quorum = 0;