diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -2177,8 +2177,10 @@
             "\nArguments:\n"
             "1. \"blockhash\"            (string, optional) The block hash to "
             "list transactions since\n"
-            "2. target_confirmations:    (numeric, optional, default=1) The "
-            "confirmations required, must be 1 or more\n"
+            "2. target_confirmations:    (numeric, optional, default=1) Return "
+            "the nth block hash from the main chain. e.g. 1 would mean the "
+            "best block hash. Note: this is not used as a filter, but only "
+            "affects [lastblock] in the return value\n"
             "3. include_watchonly:       (bool, optional, default=false) "
             "Include transactions to watch-only addresses (see "
             "'importaddress')\n"
@@ -2250,7 +2252,12 @@
             "confirmation count.\n"
             "  ],\n"
             "  \"lastblock\": \"lastblockhash\"     (string) The hash of the "
-            "last block\n"
+            "block (target_confirmations-1) from the best block on the main "
+            "chain. This is typically used to feed back into listsinceblock "
+            "the next time you call it. So you would generally use a "
+            "target_confirmations of say 6, so you will be continually "
+            "re-notified of transactions until they've reached 6 confirmations "
+            "plus any new ones\n"
             "}\n"
             "\nExamples:\n" +
             HelpExampleCli("listsinceblock", "") +