diff --git a/src/StoreKit/StoreProductParameters.cs b/src/StoreKit/StoreProductParameters.cs
index fb9848156928..23703195c8b1 100644
--- a/src/StoreKit/StoreProductParameters.cs
+++ b/src/StoreKit/StoreProductParameters.cs
@@ -27,6 +27,8 @@
 
 #nullable enable
 
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
 using CoreFoundation;
 
 namespace StoreKit {
@@ -38,19 +40,33 @@ namespace StoreKit {
 #endif
 	public partial class StoreProductParameters : DictionaryContainer {
 #if !COREBUILD
-		/// <param name="iTunesItemIdentifier">To be added.</param>
-		///         <summary>Creates a new <see cref="StoreKit.StoreProductParameters" /> for the specified ITunes identifier.</summary>
-		///         <remarks>To be added.</remarks>
+#if !XAMCORE_5_0
+		/// <summary>Creates a new <see cref="StoreKit.StoreProductParameters" /> for the specified iTunes identifier.</summary>
+		/// <param name="iTunesItemIdentifier">The 32-bit App Store item identifier to display.</param>
+		/// <remarks>Use <see cref="StoreProductParameters(long)" /> to support identifiers larger than <see cref="int.MaxValue" />.</remarks>
+		[OverloadResolutionPriorityAttribute (-1)]
+		[EditorBrowsable (EditorBrowsableState.Never)]
+		[Obsolete ("Use 'StoreProductParameters (long)' instead.")]
 		public StoreProductParameters (int iTunesItemIdentifier)
+			: this ((long) iTunesItemIdentifier)
+		{
+		}
+#endif
+
+		/// <summary>Creates a new <see cref="StoreKit.StoreProductParameters" /> for the specified 64-bit iTunes identifier.</summary>
+		/// <param name="iTunesItemIdentifier">The App Store item identifier to display.</param>
+		public StoreProductParameters (long iTunesItemIdentifier)
 			: this ()
 		{
-			ITunesItemIdentifier = iTunesItemIdentifier;
+			ITunesItemIdentifierLong = iTunesItemIdentifier;
 		}
 
-		// TODO: What is real iTunes Store item identifier length
-		/// <summary>Gets or sets the identifier for the ITunes item being advertised.</summary>
-		///         <value>To be added.</value>
-		///         <remarks>To be added.</remarks>
+#if !XAMCORE_5_0
+		/// <summary>Gets or sets the legacy 32-bit iTunes item identifier for the App Store product to display.</summary>
+		/// <value>The 32-bit App Store item identifier, or <see langword="null" /> if not set.</value>
+		/// <remarks>Use <see cref="ITunesItemIdentifierLong" /> for current identifiers and values larger than <see cref="int.MaxValue" />.</remarks>
+		[EditorBrowsable (EditorBrowsableState.Never)]
+		[Obsolete ("Use 'ITunesItemIdentifierLong' instead.")]
 		public int? ITunesItemIdentifier {
 			set {
 				SetNumberValue (SKStoreProductParameterKey.ITunesItemIdentifier, value);
@@ -59,6 +75,18 @@ public int? ITunesItemIdentifier {
 				return GetInt32Value (SKStoreProductParameterKey.ITunesItemIdentifier);
 			}
 		}
+#endif
+
+		/// <summary>Gets or sets the 64-bit iTunes item identifier for the App Store product to display.</summary>
+		/// <value>The App Store item identifier, or <see langword="null" /> if not set.</value>
+		public long? ITunesItemIdentifierLong {
+			set {
+				SetNumberValue (SKStoreProductParameterKey.ITunesItemIdentifier, value);
+			}
+			get {
+				return GetLongValue (SKStoreProductParameterKey.ITunesItemIdentifier);
+			}
+		}
 
 		/// <summary>Gets or sets a key for the affiliate token.</summary>
 		///         <value>To be added.</value>
diff --git a/tests/monotouch-test/Foundation/DictionaryContainerTest.cs b/tests/monotouch-test/Foundation/DictionaryContainerTest.cs
index 1ca025969141..e07ebca50d71 100644
--- a/tests/monotouch-test/Foundation/DictionaryContainerTest.cs
+++ b/tests/monotouch-test/Foundation/DictionaryContainerTest.cs
@@ -70,6 +70,11 @@ public void SetNumberValue_ (NSString key, nint? value)
 			SetNumberValue (key, value);
 		}
 
+		public void SetNumberValue_ (NSString key, long? value)
+		{
+			SetNumberValue (key, value);
+		}
+
 		public void SetNumberValue_ (NSString key, nuint? value)
 		{
 			SetNumberValue (key, value);
@@ -225,6 +230,25 @@ public void SetNumberValue_UInt32 ()
 			Assert.That ((int) dc.Dictionary.Count, Is.EqualTo (0), "0");
 		}
 
+		[Test]
+		public void SetNumberValue_Int64 ()
+		{
+			const long value = 2147483648L;
+			var dc = new DictionaryContainerPoker ();
+
+			Assert.Throws<ArgumentNullException> (delegate
+			{
+				dc.SetNumberValue_ (null, value);
+			}, "null key");
+
+			dc.SetNumberValue_ (key, value);
+			Assert.That ((int) dc.Dictionary.Count, Is.EqualTo (1), "1");
+			Assert.That (((NSNumber) dc.Dictionary [key]).Int64Value, Is.EqualTo (value), "value");
+
+			dc.SetNumberValue_ (key, (long?) null);
+			Assert.That ((int) dc.Dictionary.Count, Is.EqualTo (0), "0");
+		}
+
 		[Test]
 		public void SetStringValue ()
 		{
diff --git a/tests/monotouch-test/StoreKit/StoreProductParametersTest.cs b/tests/monotouch-test/StoreKit/StoreProductParametersTest.cs
new file mode 100644
index 000000000000..07c7f9e0816e
--- /dev/null
+++ b/tests/monotouch-test/StoreKit/StoreProductParametersTest.cs
@@ -0,0 +1,49 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#if !MONOMAC
+
+using Foundation;
+using StoreKit;
+
+namespace MonoTouchFixtures.StoreKit {
+
+	[TestFixture]
+	[Preserve (AllMembers = true)]
+	public class StoreProductParametersTest {
+
+		[Test]
+		public void ITunesItemIdentifier_64BitRoundtrip ()
+		{
+			const long identifier = 2147483648L;
+
+			var withCtor = new StoreProductParameters (identifier);
+			var withSetter = new StoreProductParameters {
+				ITunesItemIdentifierLong = identifier,
+			};
+
+			Assert.That (withCtor.ITunesItemIdentifierLong, Is.EqualTo (identifier), "Ctor");
+			Assert.That (withSetter.ITunesItemIdentifierLong, Is.EqualTo (identifier), "Setter");
+			Assert.That (((NSNumber) withSetter.Dictionary [SKStoreProductParameterKey.ITunesItemIdentifier]).Int64Value, Is.EqualTo (identifier), "Dictionary");
+		}
+
+#if !XAMCORE_5_0
+#pragma warning disable 618
+		[Test]
+		public void ITunesItemIdentifier_LegacyRoundtrip ()
+		{
+			const int identifier = 123456789;
+
+			var parameters = new StoreProductParameters {
+				ITunesItemIdentifier = identifier,
+			};
+
+			Assert.That (parameters.ITunesItemIdentifier, Is.EqualTo (identifier), "Legacy");
+			Assert.That (parameters.ITunesItemIdentifierLong, Is.EqualTo (identifier), "Long");
+		}
+#pragma warning restore 618
+#endif
+	}
+}
+
+#endif