Xstrata's shareholders were the last to approve the tie-up, worth £19.4bn, but they rejected a controversial "golden handcuffs" retention plan for the miner's key managers that would have paid out £140m.
Xstrata said 78.8% of shareholders voted in favour of the merger.
Glencore, which is already Xstrata's largest shareholder with 34%, had offered 3.05 new shares for every Xstrata share it did not already own.
Last week, Xstrata's second-largest investor, Qatar, said it supported the merger, despite initial concerns over its terms.
But the country's holding company said it would abstain from voting on the miner's management retention plan.
European competition regulators will decide by Thursday whether to extend their investigation into one of the sector's biggest ever acquisitions.
If the deal goes ahead, it would create the world's fourth-biggest natural resources firm - worth around $90bn (£56bn).
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