diff --git a/agent/src/main/java/org/jboss/byteman/rule/expression/InstanceOfExpression.java b/agent/src/main/java/org/jboss/byteman/rule/expression/InstanceOfExpression.java
new file mode 100644
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--- /dev/null
+++ b/agent/src/main/java/org/jboss/byteman/rule/expression/InstanceOfExpression.java
@@ -0,0 +1,82 @@
+/*
+ * JBoss, Home of Professional Open Source
+ * Copyright 2019, Red Hat and individual contributors
+ * by the @authors tag. See the copyright.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ *
+ * @authors Andrew Dinn
+ */
+
+package org.jboss.byteman.rule.expression;
+
+import org.jboss.byteman.rule.Rule;
+import org.jboss.byteman.rule.compiler.CompileContext;
+import org.jboss.byteman.rule.exception.CompileException;
+import org.jboss.byteman.rule.exception.ExecuteException;
+import org.jboss.byteman.rule.exception.TypeException;
+import org.jboss.byteman.rule.grammar.ParseNode;
+import org.jboss.byteman.rule.helper.HelperAdapter;
+import org.jboss.byteman.rule.type.Type;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+public class InstanceOfExpression  extends BooleanExpression {
+    Class<?> testType;
+    public InstanceOfExpression(Rule rule, int oper, ParseNode token, Expression left, ClassLiteralExpression right) {
+        super(rule, oper, token, left, right);
+        this.testType = null;
+    }
+    @Override
+    public Type typeCheck(Type expected) throws TypeException {
+        Type type1 = getOperand(0).typeCheck(Type.UNDEFINED);
+        Type type2 = getOperand(1).typeCheck(Type.UNDEFINED);
+        if (type1 == null || !type1.isObject()) {
+            throw new TypeException("InstanceExpression.typeCheck : left hand side of instanceof must be of object type " + getPos());
+        }
+        if (type2 == null || !type2.isObject() || !(type2.getTargetClass() == Class.class)) {
+            throw new TypeException("InstanceExpression.typeCheck : right hand side of instanceof must be a class literal " + getPos());
+        }
+        testType = (Class<?>)getOperand(1).interpret(null);
+        return Type.B;
+    }
+
+    @Override
+    public Object interpret(HelperAdapter helper) throws ExecuteException {
+        Object lhs = getOperand(0).interpret(helper);
+        return testType.isInstance(lhs);
+    }
+
+    @Override
+    public void compile(MethodVisitor mv, CompileContext compileContext) throws CompileException {
+        // make sure we are at the right source line
+        compileContext.notifySourceLine(line);
+
+        int currentStack = compileContext.getStackCount();
+        int expected = 1;
+
+        // this pushes the instance
+        getOperand(0).compile(mv, compileContext);
+        // pop the instance and replace with a boolean
+        // so no overall change
+        mv.visitTypeInsn(Opcodes.INSTANCEOF, Type.internalName(testType));
+
+        if (compileContext.getStackCount() != currentStack + expected) {
+            throw new CompileException("InstanceOfExpression.compile : invalid stack height " + compileContext.getStackCount() + " expecting " + (currentStack + expected));
+        }
+    }
+}