diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/common/StringUtils.java b/navalplanner-business/src/main/java/org/navalplanner/business/common/StringUtils.java
index 9d6c2c56e..4d8f006e0 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/common/StringUtils.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/common/StringUtils.java
@@ -30,10 +30,19 @@ public class StringUtils {
     private StringUtils() {}
 
     /**
-     * Check if a String is null or "" after being trimmed.
+     * Checks if a string is <code>null</code> or empty ("" after being
+     * trimmed).
      */
     public static boolean isEmpty(String s) {
         return s == null ? true : s.trim().equals("");
     }
 
+    /**
+     * Trims a string if is not <code>null</code>; otherwise, it returns
+     * <code>null</code>.
+     */
+    public static String trim(String s) {
+        return s == null ? null : s.trim();
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionType.java b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionType.java
index 7a6003a83..3c649b7fa 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionType.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionType.java
@@ -288,7 +288,7 @@ public class CriterionType extends BaseEntity implements
         throws InstanceNotFoundException {
 
         for (Criterion c : criterions) {
-            if (c.getName().trim().equalsIgnoreCase(criterionName)) {
+            if (c.getName().equalsIgnoreCase(criterionName)) {
                 return c;
             }
         }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/ws/resources/impl/ResourceConverter.java b/navalplanner-webapp/src/main/java/org/navalplanner/ws/resources/impl/ResourceConverter.java
index f8f1d534d..ef5660fb3 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/ws/resources/impl/ResourceConverter.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/ws/resources/impl/ResourceConverter.java
@@ -24,6 +24,7 @@ import static org.navalplanner.web.I18nHelper._;
 
 import java.util.List;
 
+import org.navalplanner.business.common.StringUtils;
 import org.navalplanner.business.common.exceptions.CreateUnvalidatedException;
 import org.navalplanner.business.resources.entities.CriterionSatisfaction;
 import org.navalplanner.business.resources.entities.Machine;
@@ -68,14 +69,16 @@ public class ResourceConverter {
 
     private final static Machine createResourceWithBasicData(
         MachineDTO machineDTO) {
-        return Machine.createUnvalidated(machineDTO.code,machineDTO.name,
-            machineDTO.description);
+        return Machine.createUnvalidated(StringUtils.trim(machineDTO.code),
+            StringUtils.trim(machineDTO.name),
+            StringUtils.trim(machineDTO.description));
     }
 
     private final static Worker createResourceWithBasicData(
         WorkerDTO workerDTO) {
-        return Worker.createUnvalidated(workerDTO.firstName, workerDTO.surname,
-            workerDTO.nif);
+        return Worker.createUnvalidated(StringUtils.trim(workerDTO.firstName),
+            StringUtils.trim(workerDTO.surname),
+            StringUtils.trim(workerDTO.nif));
     }
 
     private static void addCriterionSatisfactions(Resource resource,
@@ -99,8 +102,8 @@ public class ResourceConverter {
         throws CreateUnvalidatedException {
 
         return CriterionSatisfaction.createUnvalidated(
-            criterionSatisfactionDTO.criterionTypeName,
-            criterionSatisfactionDTO.criterionName,
+            StringUtils.trim(criterionSatisfactionDTO.criterionTypeName),
+            StringUtils.trim(criterionSatisfactionDTO.criterionName),
             resource,
             DateConverter.toDate(criterionSatisfactionDTO.startDate),
             DateConverter.toDate(criterionSatisfactionDTO.finishDate));
diff --git a/navalplanner-webapp/src/test/java/org/navalplanner/web/test/ws/resources/api/ResourceServiceTest.java b/navalplanner-webapp/src/test/java/org/navalplanner/web/test/ws/resources/api/ResourceServiceTest.java
index b27b28c3c..d948732c1 100644
--- a/navalplanner-webapp/src/test/java/org/navalplanner/web/test/ws/resources/api/ResourceServiceTest.java
+++ b/navalplanner-webapp/src/test/java/org/navalplanner/web/test/ws/resources/api/ResourceServiceTest.java
@@ -87,12 +87,16 @@ public class ResourceServiceTest {
     public void testAddResourcesWithBasicContraintViolations()
         throws InstanceNotFoundException {
 
-        String m1Code = getUniqueName();
+        String m1Code = ' ' + getUniqueName() + ' '; // Blank spaces
+                                                     // intentionally
+                                                     // added (OK).
         MachineDTO m1 = new MachineDTO(m1Code, "name", "desc");
         MachineDTO m2 = new MachineDTO("", null, ""); // Missing code and name
                                                       // (description is
                                                       // optional).
-        String w1Nif = getUniqueName();
+        String w1Nif = ' ' + getUniqueName() + ' '; // Blank spaces
+                                                    // intentionally
+                                                     // added (OK).
         WorkerDTO w1 = new WorkerDTO("w1-first-name", "w1-surname", w1Nif);
         WorkerDTO w2 = new WorkerDTO("", null, ""); // Missing first name,
                                                     // surname, and nif.
@@ -112,8 +116,8 @@ public class ResourceServiceTest {
             constraintViolations.size() == 2); // m2 constraint violations.
         assertTrue(instanceConstraintViolationsList.get(1).
             constraintViolations.size() == 3); // w2 constraint violations.
-        assertTrue(machineDAO.findByNameOrCode(m1Code).size() == 1);
-        workerDAO.findUniqueByNif(w1Nif);
+        assertTrue(machineDAO.findByNameOrCode(m1Code.trim()).size() == 1);
+        workerDAO.findUniqueByNif(w1Nif.trim());
 
     }
 
@@ -128,7 +132,9 @@ public class ResourceServiceTest {
         /* Create a resource DTO. */
         MachineDTO machineDTO = new MachineDTO(ct.getName(), "name", "desc");
         machineDTO.criterionSatisfactions.add(
-            new CriterionSatisfactionDTO(ct.getName(), "c1",
+            new CriterionSatisfactionDTO(
+                ' ' + ct.getName() + ' ', " c1 ", // Blank spaces intentionally
+                                                  // added (OK).
                 Calendar.getInstance().getTime(), null));
         machineDTO.criterionSatisfactions.add(
             new CriterionSatisfactionDTO(ct.getName(), "c2",
diff --git a/scripts/rest-clients/resources-sample.xml b/scripts/rest-clients/resources-sample.xml
index ffeb16b5f..65cd373c0 100644
--- a/scripts/rest-clients/resources-sample.xml
+++ b/scripts/rest-clients/resources-sample.xml
@@ -4,17 +4,17 @@
 
     <!--  *** Machines *** -->
     <!-- OK -->
-    <machine code="m1" name="m1-name" description="m1-desc"/>
+    <machine code=" m1 " name="m1-name" description="m1-desc"/>
     <!--  Missing code and name (description is optional). -->
     <machine code="" description=""/>
 
     <!--  *** Workers *** -->
     <!-- OK -->
-    <worker first-name="w1-firstName" surname="w1-surname" nif="w1-nif">
+    <worker first-name="w1-firstName" surname="w1-surname" nif=" w1-nif ">
         <criterion-satisfaction-list>
             <criterion-satisfaction
-                criterion-type-name="WORK_RELATIONSHIP"
-                criterion-name="hiredResourceWorkingRelationship"
+                criterion-type-name=" WORK_RELATIONSHIP "
+                criterion-name=" hiredResourceWorkingRelationship "
                 start-date="2009-01-01"
                 finish-date=""/>
             <criterion-satisfaction