A new lettuce (Lactuca sativa L.) with elliptic and dark green leaves, ‘Sambokhacheong’, which is tolerant to tipburn with good yield, was developed from a cross between ‘Meokchima’ (dark red leaves) and ‘Yeoreumcheongchima’ (high yield, green leaves). The crossing and selection for advanced lines was conducted by the pedigree method in 2006-2012. The advanced lines were evaluated for yield and adaptability at several locations in Korea (Gangwon-do, Gyeonggi-do, Chungcheongbuk-do, Chungcheongnam-do, Jeollabuk-do, Gyeongnam-do, and Jeju-do) over three years starting from 2015. The evaluations revealed that this lettuce was early- and medium-maturing leaf lettuce, with a shelf-life of four weeks at 4 ℃, longer than that of ‘Yeoreumcheongchima’. ‘Sambokhacheong’ showed no symptoms of tipburn during hot seasons in the southern parts of South Korea compared ‘Yeoreumcheongchima’. The content of bitter sesquiterpene lactones (latucin, latucin+8-deoxylactucin+lactucopicrin) of ‘Sambokhacheong’ at 57.16 (μg/g, dry weight) was higher than that of ‘Yeoreumcheongchima’. Compared with ‘Yeoreumcheongchima’, the marketable yield of ‘Sambokhacheong’ was 2% higher (at 551 g per plant) and showed late bolting at 111 days after sowing in the summer cultivation season. Its leaves are better, crispier, and sweeter than those of ‘Yeoreumcheongchima’. Therefore, we recommend the new cultivar ‘Sambokhacheong’ for cultivation in hot seasons (Registration No. 6915).