diff --git a/core/src/main/java/org/infinispan/commands/read/SizeCommand.java b/core/src/main/java/org/infinispan/commands/read/SizeCommand.java
index 3a2522cede7e..5661637ed712 100644
--- a/core/src/main/java/org/infinispan/commands/read/SizeCommand.java
+++ b/core/src/main/java/org/infinispan/commands/read/SizeCommand.java
@@ -48,7 +48,7 @@ public Integer perform(InvocationContext ctx) throws Throwable {
             CacheEntry value = contextEntries.get(entry.getKey());
             if (value != null) {
                keys.add(entry.getKey());
-               if (!value.isRemoved()) {
+               if (!value.isRemoved() && !value.isNull()) {
                   if (size++ == Integer.MAX_VALUE) {return Integer.MAX_VALUE;}
                }
             } else {
@@ -59,7 +59,7 @@ public Integer perform(InvocationContext ctx) throws Throwable {
 
       // We can only add context entries if we didn't see it in iterator and it isn't removed
       for (Map.Entry<Object, CacheEntry> entry : contextEntries.entrySet()) {
-         if (!keys.contains(entry.getKey()) && !entry.getValue().isRemoved()) {
+         if (!keys.contains(entry.getKey()) && !entry.getValue().isRemoved() && !entry.getValue().isNull()) {
             if (size++ == Integer.MAX_VALUE) { return Integer.MAX_VALUE; }
          }
       }
diff --git a/core/src/main/java/org/infinispan/iteration/impl/TransactionAwareCloseableIterator.java b/core/src/main/java/org/infinispan/iteration/impl/TransactionAwareCloseableIterator.java
index ad1230b6f01d..fb1d5cf98166 100644
--- a/core/src/main/java/org/infinispan/iteration/impl/TransactionAwareCloseableIterator.java
+++ b/core/src/main/java/org/infinispan/iteration/impl/TransactionAwareCloseableIterator.java
@@ -79,7 +79,7 @@ protected CacheEntry<K, C> getNextFromIterator() {
       while (returnedEntry == null && !contextEntries.isEmpty() && 
             (entry = contextEntries.remove(0)) != null) {
          seenContextKeys.add(entry.getKey());
-         if (!ctx.isEntryRemovedInContext(entry.getKey())) {
+         if (!ctx.isEntryRemovedInContext(entry.getKey()) && !entry.isNull()) {
             returnedEntry = filterEntry(entry);
          }
       }
@@ -89,7 +89,7 @@ protected CacheEntry<K, C> getNextFromIterator() {
             CacheEntry contextEntry;
             // If the value was in the context then we ignore the stored value since we use the context value
             if ((contextEntry = ctx.lookupEntry(iteratedEntry.getKey())) != null) {
-               if (seenContextKeys.add(contextEntry.getKey()) && !contextEntry.isRemoved() && 
+               if (seenContextKeys.add(contextEntry.getKey()) && !contextEntry.isRemoved() && !contextEntry.isNull() &&
                      (returnedEntry = filterEntry(contextEntry)) != null) {
                   break;
                }
@@ -104,7 +104,7 @@ protected CacheEntry<K, C> getNextFromIterator() {
       if (returnedEntry == null) {
          // We do a last check to make sure no additional values were added to our context while iterating
          for (CacheEntry lookedUpEntry : ctx.getLookedUpEntries().values()) {
-            if (seenContextKeys.add(lookedUpEntry.getKey()) && !lookedUpEntry.isRemoved()) {
+            if (seenContextKeys.add(lookedUpEntry.getKey()) && !lookedUpEntry.isRemoved() && !lookedUpEntry.isNull()) {
                if (returnedEntry == null) {
                   returnedEntry = lookedUpEntry;
                } else {
diff --git a/core/src/test/java/org/infinispan/api/APIRepeatableReadTxTest.java b/core/src/test/java/org/infinispan/api/APIRepeatableReadTxTest.java
new file mode 100644
index 000000000000..b9a963f51243
--- /dev/null
+++ b/core/src/test/java/org/infinispan/api/APIRepeatableReadTxTest.java
@@ -0,0 +1,26 @@
+package org.infinispan.api;
+
+import org.infinispan.configuration.cache.ConfigurationBuilder;
+import org.infinispan.manager.EmbeddedCacheManager;
+import org.infinispan.test.fwk.TestCacheManagerFactory;
+import org.infinispan.util.concurrent.IsolationLevel;
+import org.testng.annotations.Test;
+
+/**
+ * @author William Burns
+ * @since 7.2
+ */
+@Test (groups = "functional", testName = "api.APIRepeatableReadTxTest")
+public class APIRepeatableReadTxTest extends APITxTest {
+
+   @Override
+   protected EmbeddedCacheManager createCacheManager() throws Exception {
+      // start a single cache instance
+      ConfigurationBuilder c = getDefaultStandaloneCacheConfig(true);
+      c.locking().isolationLevel(IsolationLevel.REPEATABLE_READ);
+      EmbeddedCacheManager cm = TestCacheManagerFactory.createCacheManager(false);
+      cm.defineConfiguration("test", c.build());
+      cache = cm.getCache("test");
+      return cm;
+   }
+}
diff --git a/core/src/test/java/org/infinispan/api/APITxTest.java b/core/src/test/java/org/infinispan/api/APITxTest.java
new file mode 100644
index 000000000000..39977631fb2b
--- /dev/null
+++ b/core/src/test/java/org/infinispan/api/APITxTest.java
@@ -0,0 +1,106 @@
+package org.infinispan.api;
+
+import org.infinispan.configuration.cache.ConfigurationBuilder;
+import org.infinispan.manager.EmbeddedCacheManager;
+import org.infinispan.test.TestingUtil;
+import org.infinispan.test.fwk.TestCacheManagerFactory;
+import org.testng.annotations.Test;
+
+import javax.transaction.NotSupportedException;
+import javax.transaction.SystemException;
+import javax.transaction.TransactionManager;
+
+import static org.testng.AssertJUnit.assertEquals;
+
+/**
+ * @author William Burns
+ * @since 7.2
+ */
+@Test (groups = "functional", testName = "api.APITxTest")
+public class APITxTest extends APINonTxTest {
+
+   @Override
+   protected EmbeddedCacheManager createCacheManager() throws Exception {
+      // start a single cache instance
+      ConfigurationBuilder c = getDefaultStandaloneCacheConfig(true);
+      EmbeddedCacheManager cm = TestCacheManagerFactory.createCacheManager(false);
+      cm.defineConfiguration("test", c.build());
+      cache = cm.getCache("test");
+      return cm;
+   }
+
+   public void testSizeInExplicitTxWithNonExistent() throws SystemException, NotSupportedException {
+      assertEquals(0, cache.size());
+      cache.put("k", "v");
+
+      TransactionManager tm1 = TestingUtil.getTransactionManager(cache);
+      tm1.begin();
+      try {
+         cache.get("no-exist");
+         assertEquals(1, cache.size());
+         cache.put("no-exist", "value");
+         assertEquals(2, cache.size());
+      } finally {
+         tm1.rollback();
+      }
+   }
+
+   public void testSizeInExplicitTxWithRemoveNonExistent() throws SystemException, NotSupportedException {
+      assertEquals(0, cache.size());
+      cache.put("k", "v");
+
+      TransactionManager tm1 = TestingUtil.getTransactionManager(cache);
+      tm1.begin();
+      try {
+         cache.remove("no-exist");
+         assertEquals(1, cache.size());
+         cache.put("no-exist", "value");
+         assertEquals(2, cache.size());
+      } finally {
+         tm1.rollback();
+      }
+   }
+
+   public void testSizeInExplicitTxWithRemoveExistent() throws SystemException, NotSupportedException {
+      assertEquals(0, cache.size());
+      cache.put("k", "v");
+
+      TransactionManager tm1 = TestingUtil.getTransactionManager(cache);
+      tm1.begin();
+      try {
+         cache.put("exist", "value");
+         assertEquals(2, cache.size());
+         cache.remove("exist");
+         assertEquals(1, cache.size());
+      } finally {
+         tm1.rollback();
+      }
+   }
+
+   public void testSizeInExplicitTx() throws SystemException, NotSupportedException {
+      assertEquals(0, cache.size());
+      cache.put("k", "v");
+
+      TransactionManager tm1 = TestingUtil.getTransactionManager(cache);
+      tm1.begin();
+      try {
+         assertEquals(1, cache.size());
+      } finally {
+         tm1.rollback();
+      }
+   }
+
+   public void testSizeInExplicitTxWithModification() throws SystemException, NotSupportedException {
+      assertEquals(0, cache.size());
+      cache.put("k1", "v1");
+
+      TransactionManager tm1 = TestingUtil.getTransactionManager(cache);
+      tm1.begin();
+      try {
+         cache.put("k2", "v2");
+         assertEquals(2, cache.size());
+      } finally {
+         tm1.rollback();
+      }
+   }
+}