The two circa-300,000 ounce per annum producers takes the number of ASX 200 gold producers to 12.
Ramelius is up by more than 70% so far this year and is valued at A$1.7 billion. The stock hit an all-time high of $2.40.
Despite a long history of gold production, it is the first time the company has made the ASX 200. The company made the ASX 300 in 2009, but was removed only 18 months later.
Westgold is slightly lower so far in 2020 and has a market capitalisation of $909 million.
Lithium miner Orocobre and New Hope Corporation are among the companies to be removed.
There were further gold companies added to the ASX 300, with miner Alkane Resources, developer Capricorn Metals and exploration darling De Grey Mining being added.
Fortescue Metals Group was added to the ASX 20.