So, I'm having some problems getting a multi input/multi output transaction working. My code below works with 1 input and 2 output, but when adding more inputs/outputs the transaction gets rejected. I'm sure whatever I'm doing wrong in pretty simple, any ideas? Code works for this (1 input, 2 outputs): CTransaction(hash=01a3204517476812df2c2f77735a72a6d3e7eb8b9a5d5330ca433dd875fc4c3c, ver=1, vin.size=2, vout.size=4, nLockTime=0) CTxIn(COutPoint(6ee4049d6c75d6450e961446d28760207bd7036e2aa692afb80bb34245d3df84, 0), scriptSig=304502204cdfd276ff9c53bb) CTxOut(nValue=4.00000000, scriptPubKey=OP_DUP OP_HASH160 b07e181ce438) CTxOut(nValue=1.00000000, scriptPubKey=OP_DUP OP_HASH160 bf7484e469c8) Code doesn't work for this (2 input, 4 outputs): CTransaction(hash=01a3204517476812df2c2f77735a72a6d3e7eb8b9a5d5330ca433dd875fc4c3c, ver=1, vin.size=2, vout.size=4, nLockTime=0) CTxIn(COutPoint(6ee4049d6c75d6450e961446d28760207bd7036e2aa692afb80bb34245d3df84, 1), scriptSig=304502204aef3f393c273835) CTxIn(COutPoint(6ee4049d6c75d6450e961446d28760207bd7036e2aa692afb80bb34245d3df84, 0), scriptSig=304502204cdfd276ff9c53bb) CTxOut(nValue=4.00000000, scriptPubKey=OP_DUP OP_HASH160 bf7484e469c8) CTxOut(nValue=491.00000000, scriptPubKey=OP_DUP OP_HASH160 0796b7f3430f) CTxOut(nValue=4.00000000, scriptPubKey=OP_DUP OP_HASH160 b07e181ce438) CTxOut(nValue=1.00000000, scriptPubKey=OP_DUP OP_HASH160 bf7484e469c8) Pseudo code showing working transaction: // These are how the vout's are made CScript scriptPubKey; scriptPubKey.SetDestination(address); CScript s; s << OP_DUP << OP_HASH160 << scriptPubKey.GetID() << OP_EQUALVERIFY << OP_CHECKSIG; CTxOut out(nValue, s); --------------- CTransaction txNew; txNew.vin.clear(); txNew.vout.clear(); // vin and vout are already populated for(unsigned int i = 0; i < vout.size(); i++){ txNew.vout.push_back(vout[i]); } //add all vins for(unsigned int i = 0; i < vin.size(); i++){ txNew.vin.push_back(vin[i]); } //add all vins for(unsigned int i = 0; i < vin.size(); i++){ // this is signed with 2 separate keys for each vin if(!SignSignature(*keystore, prevPubKey, txNew, i, int(SIGHASH_ALL|SIGHASH_ANYONECANPAY))) printf('signing failed!\n'); // I was told I might need to serialize the inputs? Not sure how that would work } RelayTransaction(txNew, txNew.Hash()); --- CryptoFish