The biggest producer, state-owned Vinachem, saw profits go up by 31 times to VND4.098 trillion (US$175.3 million) and revenues jumping 26 percent to VND32.83 trillion.
Its subsidiaries like the Vietnam Apatite Company (410 percent), Southern Fertilizer JSC (297 percent) and DAP-Vinachem (233 percent) too reported triple-digit rises in profits.
Leading private player Duc Giang Chemicals said profits were up 5.7 times to VND2.55 trillion, four times the full-year target.
Growth was driven by higher demand from both the domestic and international markets while prices soared.
Exports topped 998,000 tons and were worth $647 million, up 43 percent and 2.8 times.
In the whole of last year exports had been worth $559 million.
But prices would fall next year as China raises its output and prices in North America have already been falling, brokerage VnDirect forecast.