diff --git a/resources/docs/Documentation.md b/resources/docs/Documentation.md
index 885d03b1d..efc483f5b 100644
--- a/resources/docs/Documentation.md
+++ b/resources/docs/Documentation.md
@@ -158,6 +158,7 @@ Note that `MessageObject` attributes which can be synchronized back to service a
 | `SameAuthor` | 4 | Check if message has same author as some another messages. |
 | `SameDateCreated` | 8 | Check if message has same date of creation as some another messages. |
 | `AllFeedsSameAccount` | 16 | Perform the check across all feeds from your account, not just "current" feed. |
+| `SameCustomId` | 32 | Check if message with same custom ID exists in RSS Guard's DB. |
 
 #### `utils` object
 | Method | How to call | Description |
diff --git a/src/librssguard/core/messageobject.cpp b/src/librssguard/core/messageobject.cpp
index fa9819b09..0d81d578f 100644
--- a/src/librssguard/core/messageobject.cpp
+++ b/src/librssguard/core/messageobject.cpp
@@ -44,6 +44,11 @@ bool MessageObject::isDuplicateWithAttribute(MessageObject::DuplicationAttribute
     bind_values.append({ QSL(":date_created"), created().toMSecsSinceEpoch() });
   }
 
+  if ((attribute_check& DuplicationAttributeCheck::SameCustomId) == DuplicationAttributeCheck::SameCustomId) {
+    where_clauses.append(QSL("custom_id = :custom_id"));
+    bind_values.append({ QSL(":custom_id"), customId() });
+  }
+
   where_clauses.append(QSL("account_id = :account_id"));
   bind_values.append({ QSL(":account_id"), accountId() });
 
@@ -219,6 +224,14 @@ int MessageObject::accountId() const {
   return m_accountId;
 }
 
+QString MessageObject::customId() const {
+  return m_message->m_customId;
+}
+
+int MessageObject::id() const {
+  return m_message->m_id;
+}
+
 QList<Label*> MessageObject::assignedLabels() const {
   return m_message->m_assignedLabels;
 }
diff --git a/src/librssguard/core/messageobject.h b/src/librssguard/core/messageobject.h
index ba83e0aa2..273894fde 100644
--- a/src/librssguard/core/messageobject.h
+++ b/src/librssguard/core/messageobject.h
@@ -14,6 +14,8 @@ class MessageObject : public QObject {
   Q_PROPERTY(QList<Label*> availableLabels READ availableLabels)
   Q_PROPERTY(QString feedCustomId READ feedCustomId)
   Q_PROPERTY(int accountId READ accountId)
+  Q_PROPERTY(int id READ id)
+  Q_PROPERTY(QString customId READ customId)
   Q_PROPERTY(QString title READ title WRITE setTitle)
   Q_PROPERTY(QString url READ url WRITE setUrl)
   Q_PROPERTY(QString author READ author WRITE setAuthor)
@@ -56,7 +58,10 @@ class MessageObject : public QObject {
       // Compare with all messages from the account not only with messages from same feed.
       // Note that this value must be used via bitwise OR with other values,
       // for example 2 | 4 | 16.
-      AllFeedsSameAccount = 16
+      AllFeedsSameAccount = 16,
+
+      // Messages with same custom ID as provided by feed/service.
+      SameCustomId = 32
     };
 
     Q_ENUM(DuplicationAttributeCheck)
@@ -91,8 +96,13 @@ class MessageObject : public QObject {
 
     // Generic Message's properties bindings.
     QString feedCustomId() const;
+
     int accountId() const;
 
+    QString customId() const;
+
+    int id() const;
+
     QString title() const;
     void setTitle(const QString& title);