Abstract: In this paper, karyotypes from fifteen populations in thirteen species of Euphorbia (Euphorbiaceae) from China were investigated. The results were as follows: 2n=2x=22=20m (2SAT)+2sm for Euphorbia humifusa (Wangjiang, Sichuan); 2n=2x=22=18m+4sm for E. humifusa (Hongqicun, Beijing); 2n=4x=40=40m for E. thymifolia; 2n=4x=40=36m+4sm for E. maculata; 2n=8x=56=40m+8sm+8st for E. marginata; 2n=4x=40=32m+8sm for E. milii; 2n=6x=60=6m+36sm+12st+6t for E. neriifolia; 2n=6x=60=24m+24sm+12st for E. antiquorum; 2n=4x=28=24m(3SAT)+4sm for E. pulcherrima; 2n=4x=28=16m+12sm for E. cyathophora; 2n=4x=28=28m for E. dentata; 2n=2x=20=12m+8sm for E. lathyris; 2n=6x= 42=36m+6sm for E. helioscopia; 2n=2x=20=14m+6sm for E. esula (Chenjiagou, Beijing); 2n=4x=40=32m+8sm for E. esula (Yingtaogou, Beijing). The karyotypes of two species, E. thymifolia and E. maculata, and the tetraploidy karyotype of E. esula were reported for the first time.