diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/FHIRPathEngine.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/FHIRPathEngine.java
index 7875be585..5fe9080c5 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/FHIRPathEngine.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/FHIRPathEngine.java
@@ -1,33 +1,33 @@
 package org.hl7.fhir.dstu2.utils;
 
-/*
-  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
-  
-  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
-    
-   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
-     prior written permission.
-  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
-  
- */
+/*
+  Copyright (c) 2011+, HL7, Inc.
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+    
+   * Redistributions of source code must retain the above copyright notice, this 
+     list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+   * Neither the name of HL7 nor the names of its contributors may be used to 
+     endorse or promote products derived from this software without specific 
+     prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  POSSIBILITY OF SUCH DAMAGE.
+  
+ */
 
 
 
@@ -2112,13 +2112,15 @@ public class FHIRPathEngine {
 
   private List<Base> funcReplaceMatches(ExecutionContext context, List<Base> focus, ExpressionNode exp) throws PathEngineException  {
     List<Base> result = new ArrayList<Base>();
-    String sw = convertToString(execute(context, focus, exp.getParameters().get(0), true));
+    String regex = convertToString(execute(context, focus, exp.getParameters().get(0), true));
+    String repl = convertToString(execute(context, focus, exp.getParameters().get(1), true));
 
-    if (focus.size() == 1 && !Utilities.noString(sw))
-      result.add(new BooleanType(convertToString(focus.get(0)).contains(sw)));
-    else
-      result.add(new BooleanType(false));
-		return result;
+    if (focus.size() == 1 && !Utilities.noString(regex)) {
+      result.add(new StringType(convertToString(focus.get(0)).replaceAll(regex, repl)));
+    } else {
+      result.add(new StringType(convertToString(focus.get(0))));
+    }
+    return result;
 	}
 
 
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/FHIRPathEngine.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/FHIRPathEngine.java
index 54191747f..0e50f7b6f 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/FHIRPathEngine.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/FHIRPathEngine.java
@@ -1,33 +1,33 @@
 package org.hl7.fhir.dstu3.utils;
 
-/*
-  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
-  
-  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
-    
-   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
-     prior written permission.
-  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
-  
- */
+/*
+  Copyright (c) 2011+, HL7, Inc.
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+    
+   * Redistributions of source code must retain the above copyright notice, this 
+     list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+   * Neither the name of HL7 nor the names of its contributors may be used to 
+     endorse or promote products derived from this software without specific 
+     prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  POSSIBILITY OF SUCH DAMAGE.
+  
+ */
 
 
 
@@ -2244,12 +2244,14 @@ public class FHIRPathEngine {
 
   private List<Base> funcReplaceMatches(ExecutionContext context, List<Base> focus, ExpressionNode exp) throws FHIRException {
     List<Base> result = new ArrayList<Base>();
-    String sw = convertToString(execute(context, focus, exp.getParameters().get(0), true));
+    String regex = convertToString(execute(context, focus, exp.getParameters().get(0), true));
+    String repl = convertToString(execute(context, focus, exp.getParameters().get(1), true));
 
-    if (focus.size() == 1 && !Utilities.noString(sw))
-      result.add(new BooleanType(convertToString(focus.get(0)).contains(sw)));
-    else
-      result.add(new BooleanType(false));
+    if (focus.size() == 1 && !Utilities.noString(regex)) {
+      result.add(new StringType(convertToString(focus.get(0)).replaceAll(regex, repl)));
+    } else {
+      result.add(new StringType(convertToString(focus.get(0))));
+    }
     return result;
   }