Cameron said that an EU summit in Brussels which discussed the eurozone's debt crisis was a "good meeting" in that it had focused on growth and the need for structural reforms.
"There were good innovative ideas that can help growth in Europe, but frankly there were some bad ideas too. A financial transaction tax is a bad idea," Cameron told reporters as he left the summit.
"It will put up the cost of people's insurance, put up the cost of people's pensions, it would cost many, many jobs, and it would make Europe less competitive and I'll fight it all the way."
Britain says the French-inspired tax would undermine London as a global financial centre.
Earlier on Wednesday the European parliament adopted proposals on the FTT by a strong majority.
It passed the resolution with 487 votes in favour, 152 against and 46 abstentions, calling for the implementation of the tax by the beginning of 2015 "even if only some member states opt for it".
Nine countries have come out in favour of the FTT -- Austria, Belgium, Finland, France, Germany, Greece, Italy, Portugal and Spain.
"The FTT is an integral part of an exit from crisis," said parliamentary rapporteur Anni Podimata, a Greek Socialist. "It will bring a fairer distribution of the weight of the crisis."
Parliament approved the tax rates proposed by the Commission, 0.1 per cent for transactions of shares and bonds, and 0.01 per cent for derivatives.
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