diff --git a/packages/pg/lib/utils.js b/packages/pg/lib/utils.js
index e23a55e9a..35aa50a68 100644
--- a/packages/pg/lib/utils.js
+++ b/packages/pg/lib/utils.js
@@ -93,8 +93,13 @@ function prepareObject(val, seen) {
 }
 
 function dateToString(date) {
+  // Validate date to prevent serialization of invalid dates as "NaN-NaN-NaN..."
+  // Invalid dates can occur from new Date(undefined), new Date(NaN), etc.
+  // See https://github.com/brianc/node-postgres/issues/3318
+  if (!date || !(date instanceof Date) || isNaN(date.getTime())) {
+    throw new TypeError('Cannot serialize invalid date')
+  }
   let offset = -date.getTimezoneOffset()
-
   let year = date.getFullYear()
   const isBCYear = year < 1
   if (isBCYear) year = Math.abs(year) + 1 // negative years are 1 off their BC representation
@@ -127,6 +132,12 @@ function dateToString(date) {
 }
 
 function dateToStringUTC(date) {
+  // Validate date to prevent serialization of invalid dates as "NaN-NaN-NaN..."
+  // Invalid dates can occur from new Date(undefined), new Date(NaN), etc.
+  // See https://github.com/brianc/node-postgres/issues/3318
+  if (!date || !(date instanceof Date) || isNaN(date.getTime())) {
+    throw new TypeError('Cannot serialize invalid date')
+  }
   let year = date.getUTCFullYear()
   const isBCYear = year < 1
   if (isBCYear) year = Math.abs(year) + 1 // negative years are 1 off their BC representation
diff --git a/packages/pg/test/integration/gh-issues/2862-tests.js b/packages/pg/test/integration/gh-issues/2862-tests.js
index 5e36d21ef..5b80692f1 100644
--- a/packages/pg/test/integration/gh-issues/2862-tests.js
+++ b/packages/pg/test/integration/gh-issues/2862-tests.js
@@ -1,20 +1,25 @@
 'use strict'
-
 const helper = require('../test-helper')
 const assert = require('assert')
 const vm = require('vm')
-
 const suite = new helper.Suite()
 
 suite.testAsync('Handle date objects as Date', async () => {
-  const crossRealmDate = await vm.runInNewContext('new Date()')
+  // Create a valid timestamp
+  const timestamp = Date.now()
+  // Create cross-realm date with valid timestamp and immediately get its value
+  const crossRealmDate = await vm.runInNewContext(`new Date(${timestamp})`)
   assert(!(crossRealmDate instanceof Date))
-  const date = new Date(crossRealmDate.getTime())
+  // Extract the time value while it's still valid
+  const crossRealmTime = crossRealmDate.getTime()
+  // Create local dates from the timestamps
+  const date = new Date(timestamp)
+  const crossRealmDateLocal = new Date(crossRealmTime)
   const client = new helper.pg.Client()
   await client.connect()
-
   await client.query('CREATE TEMP TABLE foo(bar timestamptz, bar2 timestamptz)')
-  await client.query('INSERT INTO foo(bar, bar2) VALUES($1, $2)', [date, crossRealmDate])
+  // Use the local date objects, not the cross-realm one
+  await client.query('INSERT INTO foo(bar, bar2) VALUES($1, $2)', [date, crossRealmDateLocal])
   const results = await client.query('SELECT * FROM foo')
   const row = results.rows[0]
   assert.deepStrictEqual(row.bar, date)
diff --git a/packages/pg/test/unit/utils-tests.js b/packages/pg/test/unit/utils-tests.js
index 5f75f6c2d..8a03935e5 100644
--- a/packages/pg/test/unit/utils-tests.js
+++ b/packages/pg/test/unit/utils-tests.js
@@ -314,3 +314,28 @@ testEscapeIdentifier(
   'hello \\ \' " world',
   '"hello \\ \' "" world"'
 )
+
+test('prepareValue: invalid date from undefined throws error', function () {
+  assert.throws(() => {
+    utils.prepareValue(new Date(undefined))
+  }, /Cannot serialize invalid date/)
+})
+
+test('prepareValue: invalid date from NaN throws error', function () {
+  assert.throws(() => {
+    utils.prepareValue(new Date(NaN))
+  }, /Cannot serialize invalid date/)
+})
+
+test('prepareValue: invalid date from invalid string throws error', function () {
+  assert.throws(() => {
+    utils.prepareValue(new Date('invalid'))
+  }, /Cannot serialize invalid date/)
+})
+
+test('prepareValue: valid date still works correctly', function () {
+  const date = new Date('2024-01-01T12:00:00Z')
+  const result = utils.prepareValue(date)
+  assert(typeof result === 'string')
+  assert(result.includes('2024'))
+})