Mexico's central bank bought more than 90 tonnes of gold between January and March, according to figures from the International Monetary Fund (IMF).
It is one of a number of central banks in emerging markets buying large quantities of gold, with its price near record highs.
Banks are seeking to diversify their reserves out of US dollars.
Mexico now owns 100.15 tonnes of gold, data on the IMF website showed. At the end of January it held 6.84 tonnes.
Mexico's purchase is equivalent to about 3.5% of annual mined output.
The country now owns $4.93bn (£2.98bn) worth of gold, which hit a record price of $1,575.79 an ounce on Monday.
It takes Mexico to 33rd place on the list of the world's top gold holders.
"Mexico seems to be following the trend established by several other central banks recently and is moving toward restoring a prior balance between gold and currency reserves," said George Milling-Stanley from the World Gold Council.
India recently bought 200 tonnes of gold from the IMF.
The latest IMF figures also show that Russia bought 18.8 tonnes and Thailand 9.3 tonnes, the World Gold Council said.
The US is the largest official holder of gold, with 8,133 tonnes.
China is the sixth largest holder, with 1,054.1 tonnes.
Gold is seen as a haven, attracting investors in times of uncertainty.
Its price has risen 11% so far this year, thanks largely to the decline in the value of the US dollar against a basket of currencies, as well as concern over the debt crisis in Europe and instability in the Middle East.