The Caulfield Guineas is a Melbourne Racing Club Australian Group 1 Thoroughbred horse race held over 1600 metres (approx 1 mile) at set weights for 3 year old horses, held annually on the second Saturday in October and forms part of the Spring Carnival at Caulfield Racecourse. Total prize money is AUD$ 1 million. The Guineas, as the race is affectionally known, starts the three day Caulfield carnival; the G1 Toorak Handicap and G1 Yalumba Stakes are also held on Guineas day; the fillies equivalent, the G1 Thousand Guineas, is run on the Wednesday following the Guineas and the G1 Caulfield Cup finishes the carnival the following Saturday.
- From 1940 to 1943 the race was run at Flemington Racecourse.
Regarded as one of the blue riband events for three year olds, the Guineas is regarded as a stallion making race for the winner, and has been won by a host of star gallopers who gave gone on to multiple G1 success; the past three years, for example, have included Starspangledbanner (2010 G1 Oakleigh Plate, 2010 G1 Golden Jubilee Stakes), Whobegotyou (2009 G1 Yalumba Stakes), Weekend Hussler (six other G1 races including 2007 G1 Ascot Vale Stakes, 2008 G1 Randwick Guineas and 2008 G1 George Ryder Stakes). Earlier winners include celebrated champion sires Lonhro (2001, 11 G1 wins) and Redoute's Choice (1999, 4 G1 wins). Looking further back, other outstanding winners include Mahogany (1993, 8 G1 wins), Red Anchor (1984, 4 G1 wins), champion sprinter Manikato (12 official G1 wins, 18 wins in races that are classified as G1 today), 2YO Triple Crown winner Luskin Star (1977, 4 G1 wins), Surround (1976, first and only filly to win the weight-for-age championship of Australasia, the Cox Plate), Vain (1969, 6 G1 wins and champion sire), Storm Queen (1966, 5 G1 wins), the inaugural Australian Racing Hall of Fame inductee Tulloch (1957, 14 G1 wins), and Ajax II (14 G1 wins and fellow Australian Racing Hall of Fame inductee, and still revered in Australia as the shortest priced favourite to lose in Australian racing history, at 40/1 on ($1.02) in the 1939 Rawson Stakes).