diff --git a/src/main/scala/zio/nio/channels/SelectableChannel.scala b/src/main/scala/zio/nio/channels/SelectableChannel.scala
index b1214a6a..e1027779 100644
--- a/src/main/scala/zio/nio/channels/SelectableChannel.scala
+++ b/src/main/scala/zio/nio/channels/SelectableChannel.scala
@@ -9,6 +9,7 @@ import java.nio.channels.{
   SocketChannel => JSocketChannel
 }
 
+import zio.nio.channels.SelectionKey.Operation
 import zio.nio.channels.spi.SelectorProvider
 import zio.nio.{ Buffer, SocketAddress, SocketOption }
 import zio.{ IO, UIO }
@@ -20,8 +21,9 @@ trait SelectableChannel extends Channel {
   final val provider: UIO[SelectorProvider] =
     IO.effectTotal(new SelectorProvider(channel.provider()))
 
-  final val validOps: UIO[Int] =
+  final val validOps: UIO[Set[Operation]] =
     IO.effectTotal(channel.validOps())
+      .map(Operation.fromInt(_))
 
   final val isRegistered: UIO[Boolean] =
     IO.effectTotal(channel.isRegistered())
@@ -29,12 +31,21 @@ trait SelectableChannel extends Channel {
   final def keyFor(sel: Selector): UIO[Option[SelectionKey]] =
     IO.effectTotal(Option(channel.keyFor(sel.selector)).map(new SelectionKey(_)))
 
-  final def register(sel: Selector, ops: Int, att: Option[AnyRef]): IO[IOException, SelectionKey] =
-    IO.effect(new SelectionKey(channel.register(sel.selector, ops, att.orNull)))
+  final def register(sel: Selector, ops: Set[Operation], att: Option[AnyRef]): IO[IOException, SelectionKey] =
+    IO.effect(new SelectionKey(channel.register(sel.selector, Operation.toInt(ops), att.orNull)))
       .refineToOrDie[IOException]
 
-  final def register(sel: Selector, ops: Int): IO[IOException, SelectionKey] =
-    IO.effect(new SelectionKey(channel.register(sel.selector, ops))).refineToOrDie[IOException]
+  final def register(sel: Selector, ops: Set[Operation]): IO[IOException, SelectionKey] =
+    IO.effect(new SelectionKey(channel.register(sel.selector, Operation.toInt(ops))))
+      .refineToOrDie[IOException]
+
+  final def register(sel: Selector, op: Operation, att: Option[AnyRef]): IO[IOException, SelectionKey] =
+    IO.effect(new SelectionKey(channel.register(sel.selector, op.intVal, att.orNull)))
+      .refineToOrDie[IOException]
+
+  final def register(sel: Selector, op: Operation): IO[IOException, SelectionKey] =
+    IO.effect(new SelectionKey(channel.register(sel.selector, op.intVal)))
+      .refineToOrDie[IOException]
 
   final def configureBlocking(block: Boolean): IO[IOException, Unit] =
     IO.effect(channel.configureBlocking(block)).unit.refineToOrDie[IOException]
diff --git a/src/main/scala/zio/nio/channels/SelectionKey.scala b/src/main/scala/zio/nio/channels/SelectionKey.scala
index 9a5f2165..ab7265ae 100644
--- a/src/main/scala/zio/nio/channels/SelectionKey.scala
+++ b/src/main/scala/zio/nio/channels/SelectionKey.scala
@@ -14,6 +14,23 @@ object SelectionKey {
     case e: CancelledKeyException => e
   }
 
+  sealed abstract class Operation(val intVal: Int)
+
+  object Operation {
+
+    final case object Read    extends Operation(JSelectionKey.OP_READ)
+    final case object Write   extends Operation(JSelectionKey.OP_WRITE)
+    final case object Connect extends Operation(JSelectionKey.OP_CONNECT)
+    final case object Accept  extends Operation(JSelectionKey.OP_ACCEPT)
+
+    final val fullSet: Set[Operation] = Set(Read, Write, Connect, Accept)
+
+    final def fromInt(ops: Int): Set[Operation] =
+      fullSet.filter(op => (ops & op.intVal) != 0)
+
+    final def toInt(set: Set[Operation]): Int =
+      set.foldLeft(0)((ops, op) => ops | op.intVal)
+  }
 }
 
 class SelectionKey(private[nio] val selectionKey: JSelectionKey) {
@@ -32,16 +49,20 @@ class SelectionKey(private[nio] val selectionKey: JSelectionKey) {
   final val cancel: UIO[Unit] =
     IO.effectTotal(selectionKey.cancel())
 
-  final val interestOps: IO[CancelledKeyException, Int] =
-    IO.effect(selectionKey.interestOps()).refineToOrDie[CancelledKeyException]
+  final val interestOps: IO[CancelledKeyException, Set[Operation]] =
+    IO.effectTotal(selectionKey.interestOps())
+      .map(Operation.fromInt(_))
+      .refineToOrDie[CancelledKeyException]
 
-  final def interestOps(ops: Int): IO[CancelledKeyException, SelectionKey] =
-    IO.effect(selectionKey.interestOps(ops))
-      .map(new SelectionKey(_))
+  final def interestOps(ops: Set[Operation]): IO[CancelledKeyException, Unit] =
+    IO.effect(selectionKey.interestOps(Operation.toInt(ops)))
+      .unit
       .refineToOrDie[CancelledKeyException]
 
-  final val readyOps: IO[CancelledKeyException, Int] =
-    IO.effect(selectionKey.readyOps()).refineToOrDie[CancelledKeyException]
+  final val readyOps: IO[CancelledKeyException, Set[Operation]] =
+    IO.effect(selectionKey.readyOps())
+      .map(Operation.fromInt(_))
+      .refineToOrDie[CancelledKeyException]
 
   final def isReadable: IO[CancelledKeyException, Boolean] =
     IO.effect(selectionKey.isReadable()).refineOrDie(JustCancelledKeyException)
diff --git a/src/test/scala/zio/nio/channels/SelectorSuite.scala b/src/test/scala/zio/nio/channels/SelectorSuite.scala
index 83f1ac82..f9262f8e 100644
--- a/src/test/scala/zio/nio/channels/SelectorSuite.scala
+++ b/src/test/scala/zio/nio/channels/SelectorSuite.scala
@@ -1,10 +1,11 @@
 package zio.nio.channels
 
-import java.nio.channels.{ CancelledKeyException, SelectionKey => JSelectionKey, SocketChannel => JSocketChannel }
+import java.nio.channels.{ CancelledKeyException, SocketChannel => JSocketChannel }
 
 import testz.{ Harness, assert }
 import zio._
 import zio.clock.Clock
+import zio.nio.channels.SelectionKey.Operation
 import zio.nio.{ Buffer, SocketAddress }
 
 object SelectorSuite extends DefaultRuntime {
@@ -36,7 +37,7 @@ object SelectorSuite extends DefaultRuntime {
                         clientOpt <- channel.accept
                         client    = clientOpt.get
                         _         <- client.configureBlocking(false)
-                        _         <- client.register(selector, JSelectionKey.OP_READ)
+                        _         <- client.register(selector, Operation.Read)
                       } yield ()
                     } *>
                       IO.whenM(safeStatusCheck(key.isReadable)) {
@@ -62,7 +63,7 @@ object SelectorSuite extends DefaultRuntime {
           channel  <- ServerSocketChannel.open
           _        <- channel.bind(address)
           _        <- channel.configureBlocking(false)
-          _        <- channel.register(selector, JSelectionKey.OP_ACCEPT)
+          _        <- channel.register(selector, Operation.Accept)
           buffer   <- Buffer.byte(256)
           _        <- started.succeed(())