diff --git a/src/main/client/connect.c b/src/main/client/connect.c
index 54f0e0cb26..67831aef24 100644
--- a/src/main/client/connect.c
+++ b/src/main/client/connect.c
@@ -144,6 +144,10 @@ int AerospikeClientConnect(AerospikeClient *self)
     return 0;
 }
 
+extern as_status as_config_set_user_from_py_username_and_py_password(
+    as_error *err, as_config *config, PyObject *py_username,
+    PyObject *py_password);
+
 /**
  *******************************************************************************************************
  * Establishes a connection to the Aerospike DB instance.
@@ -176,11 +180,11 @@ PyObject *AerospikeClient_Connect(AerospikeClient *self, PyObject *args,
         return NULL;
     }
 
-    if (py_username && PyUnicode_Check(py_username) && py_password &&
-        PyUnicode_Check(py_password)) {
-        char *username = (char *)PyUnicode_AsUTF8(py_username);
-        char *password = (char *)PyUnicode_AsUTF8(py_password);
-        as_config_set_user(&self->as->config, username, password);
+    if (as_config_set_user_from_py_username_and_py_password(
+            &err, &self->as->config, py_username, py_password) !=
+        AEROSPIKE_OK) {
+        raise_exception(&err);
+        return NULL;
     }
 
     if (AerospikeClientConnect(self) == -1) {
diff --git a/src/main/client/type.c b/src/main/client/type.c
index b77e5a3290..565cd77ebe 100644
--- a/src/main/client/type.c
+++ b/src/main/client/type.c
@@ -573,6 +573,32 @@ int does_py_dict_contain_valid_keys(as_error *err, PyObject *py_dict,
 
 #define CLIENT_CONFIG_DICTIONARY_ADJECTIVE_FOR_ERROR_MESSAGE "client config"
 
+as_status as_config_set_user_from_py_username_and_py_password(
+    as_error *err, as_config *config, PyObject *py_username,
+    PyObject *py_password)
+{
+    if (py_username && PyUnicode_Check(py_username) && py_password &&
+        PyUnicode_Check(py_password)) {
+        char *username = (char *)PyUnicode_AsUTF8(py_username);
+        if (username && strlen(username) >= AS_USER_SIZE) {
+            return as_error_update(
+                err, AEROSPIKE_ERR_PARAM,
+                "Username must be at most 63 characters long.")
+        }
+
+        char *password = (char *)PyUnicode_AsUTF8(py_password);
+        if (password && strlen(password) >= AS_PASSWORD_SIZE) {
+            return as_error_update(
+                err, AEROSPIKE_ERR_PARAM,
+                "Password must be at most 63 characters long.")
+        }
+
+        as_config_set_user(config, username, password);
+    }
+
+    return AEROSPIKE_OK;
+}
+
 static int AerospikeClient_Type_Init(AerospikeClient *self, PyObject *args,
                                      PyObject *kwds)
 {
@@ -1290,11 +1316,11 @@ static int AerospikeClient_Type_Init(AerospikeClient *self, PyObject *args,
 
     PyObject *py_user_name = PyDict_GetItemString(py_config, "user");
     PyObject *py_user_pwd = PyDict_GetItemString(py_config, "password");
-    if (py_user_name && PyUnicode_Check(py_user_name) && py_user_pwd &&
-        PyUnicode_Check(py_user_pwd)) {
-        char *username = (char *)PyUnicode_AsUTF8(py_user_name);
-        char *password = (char *)PyUnicode_AsUTF8(py_user_pwd);
-        as_config_set_user(&config, username, password);
+
+    if (as_config_set_user_from_py_username_and_py_password(
+            &constructor_err, &config, py_user_name, py_user_pwd) !=
+        AEROSPIKE_OK) {
+        goto RAISE_EXCEPTION_WITH_AS_ERROR;
     }
 
     self->as = aerospike_new(&config);
diff --git a/test/new_tests/test_client_config_level_options.py b/test/new_tests/test_client_config_level_options.py
index f7b7c027e6..f4f68bd5da 100644
--- a/test/new_tests/test_client_config_level_options.py
+++ b/test/new_tests/test_client_config_level_options.py
@@ -523,9 +523,35 @@ def test_invalid_read_touch_ttl_percent(self, policy_name: str):
                 },
                 # Tests that fail to connect should expect any of these exceptions
                 pytest.raises((e.ConnectionError, e.TimeoutError, e.ClientError))
-            )
+            ),
         ]
     )
     def test_client_class_constructor(self, config: dict, context):
         with context:
             aerospike.Client(config)
+
+    LONG_USERNAME = "a" * 63
+    LONG_PASSWORD = "a" * 63
+
+    @pytest.fixture
+    def setup_user_with_long_username_and_password(self):
+        self.client.admin_create_user(self.LONG_USERNAME, self.LONG_PASSWORD, [])
+
+        yield
+
+        self.client.admin_drop_user(self.LONG_USERNAME)
+
+    @pytest.mark.parametrize(
+        "username, password",
+        [
+            (LONG_USERNAME + "a", LONG_PASSWORD),
+            (LONG_USERNAME, LONG_PASSWORD + "a")
+        ]
+    )
+    def test_passing_credentials_too_long(self, setup_user_with_long_username_and_password, username, password):
+        config = copy.deepcopy(gconfig)
+        config["user"] = username
+        config["password"] = password
+
+        with pytest.raises(e.ParamError):
+            aerospike.client(config)