diff --git a/libuavcan/include/uavcan/transport/outgoing_transfer_registry.hpp b/libuavcan/include/uavcan/transport/outgoing_transfer_registry.hpp
index 60e529b684..f3a399ead5 100644
--- a/libuavcan/include/uavcan/transport/outgoing_transfer_registry.hpp
+++ b/libuavcan/include/uavcan/transport/outgoing_transfer_registry.hpp
@@ -41,6 +41,9 @@ public:
         assert(transfer_type != TransferTypeServiceResponse);
     }
 
+    DataTypeID getDataTypeID() const { return data_type_id_; }
+    TransferType getTransferType() const { return TransferType(transfer_type_); }
+
     bool operator==(const OutgoingTransferRegistryKey& rhs) const
     {
         return
@@ -66,6 +69,7 @@ class IOutgoingTransferRegistry
 public:
     virtual ~IOutgoingTransferRegistry() { }
     virtual TransferID* accessOrCreate(const OutgoingTransferRegistryKey& key, MonotonicTime new_deadline) = 0;
+    virtual bool exists(DataTypeID dtid, TransferType tt) const = 0;
     virtual void cleanup(MonotonicTime deadline) = 0;
 };
 
@@ -104,6 +108,23 @@ UAVCAN_PACKED_END
         }
     };
 
+    class ExistenceCheckingPredicate
+    {
+        const DataTypeID dtid_;
+        const TransferType tt_;
+
+    public:
+        ExistenceCheckingPredicate(DataTypeID dtid, TransferType tt)
+        : dtid_(dtid)
+        , tt_(tt)
+        { }
+
+        bool operator()(const OutgoingTransferRegistryKey& key, const Value&) const
+        {
+            return dtid_ == key.getDataTypeID() && tt_ == key.getTransferType();
+        }
+    };
+
     Map<OutgoingTransferRegistryKey, Value, NumStaticEntries> map_;
 
 public:
@@ -126,6 +147,11 @@ public:
         return &p->tid;
     }
 
+    bool exists(DataTypeID dtid, TransferType tt) const
+    {
+        return NULL != map_.findFirstKey(ExistenceCheckingPredicate(dtid, tt));
+    }
+
     void cleanup(MonotonicTime ts)
     {
         map_.removeWhere(DeadlineExpiredPredicate(ts));
diff --git a/libuavcan/test/transport/outgoing_transfer_registry.cpp b/libuavcan/test/transport/outgoing_transfer_registry.cpp
index 2945ee9cc1..2456df5030 100644
--- a/libuavcan/test/transport/outgoing_transfer_registry.cpp
+++ b/libuavcan/test/transport/outgoing_transfer_registry.cpp
@@ -20,9 +20,9 @@ TEST(OutgoingTransferRegistry, Basic)
     const OutgoingTransferRegistryKey keys[NUM_KEYS] =
     {
         OutgoingTransferRegistryKey(123, uavcan::TransferTypeMessageUnicast,   42),
-        OutgoingTransferRegistryKey(123, uavcan::TransferTypeMessageBroadcast, 0),
-        OutgoingTransferRegistryKey(123, uavcan::TransferTypeServiceRequest,   2),
-        OutgoingTransferRegistryKey(123, uavcan::TransferTypeMessageUnicast,   4),
+        OutgoingTransferRegistryKey(321, uavcan::TransferTypeMessageBroadcast, 0),
+        OutgoingTransferRegistryKey(213, uavcan::TransferTypeServiceRequest,   2),
+        OutgoingTransferRegistryKey(312, uavcan::TransferTypeMessageUnicast,   4),
         OutgoingTransferRegistryKey(456, uavcan::TransferTypeServiceRequest,   2)
     };
 
@@ -51,6 +51,20 @@ TEST(OutgoingTransferRegistry, Basic)
 
     ASSERT_FALSE(otr.accessOrCreate(keys[4], tsMono(1000000)));        // Still OOM
 
+    /*
+     * Checking existence
+     * Exist: 0, 1, 2, 3
+     * Does not exist: 4
+     */
+    ASSERT_TRUE(otr.exists(keys[1].getDataTypeID(), keys[1].getTransferType()));
+    ASSERT_TRUE(otr.exists(keys[0].getDataTypeID(), keys[0].getTransferType()));
+    ASSERT_TRUE(otr.exists(keys[3].getDataTypeID(), keys[3].getTransferType()));
+    ASSERT_TRUE(otr.exists(keys[2].getDataTypeID(), keys[2].getTransferType()));
+
+    ASSERT_FALSE(otr.exists(keys[1].getDataTypeID(), keys[2].getTransferType()));  // Invalid combination
+    ASSERT_FALSE(otr.exists(keys[0].getDataTypeID(), keys[1].getTransferType()));  // Invalid combination
+    ASSERT_FALSE(otr.exists(keys[4].getDataTypeID(), keys[4].getTransferType()));  // Plain missing
+
     /*
      * Cleaning up
      */