diff --git a/src/wallet/asyncrpcoperation_sendmany.cpp b/src/wallet/asyncrpcoperation_sendmany.cpp
index de3ee1077..880555b19 100644
--- a/src/wallet/asyncrpcoperation_sendmany.cpp
+++ b/src/wallet/asyncrpcoperation_sendmany.cpp
@@ -196,6 +196,9 @@ bool AsyncRPCOperation_sendmany::main_impl() {
     CAmount sendAmount = z_outputs_total + t_outputs_total;
     CAmount targetAmount = sendAmount + minersFee;
 
+    assert(!isfromtaddr_ || z_inputs_total == 0);
+    assert(!isfromzaddr_ || t_inputs_total == 0);
+
     if (isfromtaddr_ && (t_inputs_total < targetAmount)) {
         throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, strprintf("Insufficient transparent funds, have %ld, need %ld", t_inputs_total, targetAmount));
     }