‘Baegilmi’ is an extremely early maturing rice variety that can be harvested within 100 days after transplanting, and also exhibits strong blast resistance and good grain appearance. From a mutant population of ‘Koshihikari’ treated with ethyl methanesulfonate, a promising line, ‘Suweon 559’, was selected through pedigree breeding and yield trials, and subsequently registered as ‘Baegilmi’. According to the 3-year (2012–2014) regional adaptability tests, the average heading date of Baegilmi in ordinary planting was July 14^th, which was 23 and 9 days earlier than that of the check varieties ‘Hwaseong’ and ‘Odae’, respectively. The milled rice yield of ‘Baegilmi’ was 4.53 MT/ha in ordinary planting (83% and 98% of ‘Hwaseong’ and ‘Odae’, respectively). ‘Baegilmi’ had a culm length of 75 cm (10 cm shorter than ‘Hwaseong’), a panicle length of 21 cm (similar to ‘Hwaseong’), and 12 panicles per plant (two fewer than ‘Hwaseong’). The brown rice of ‘Baegilmi’ was slightly more slender than ‘Hwaseong’, with a 1,000 grain weight of 20.6 g and length/width ratio of 1.92. The milled rice of ‘Baegilmi’ was translucent, with a protein content of 8.4% (1.7% higher than ‘Hwaseong’) and an amylose content of 18.6% (similar to ‘Hwaseong’). ‘Baegilmi’ exhibited strong blast resistance, but was susceptible to bacterial blight, viral diseases, and insect pests. The release of ‘Baegilmi’ is expected to provide a useful early-maturing rice variety that can be used in diverse cropping systems in paddy fields (Registration No. 6805).