Abstract: The karyotypes of 3 species in Nicotiana ( N. glutionsa , N. nesophila and N. stocktonii ) were studied. The results show that N. glutinosa is a diploid, with a karyotype formula of 2n=24=10M+10m+4sm(2SAT), while N. nesophila is a probable amphidiploid, with 2n=48=6M+20m(2SAT)+18sm+4st, and N. stocktonii is also a probable amphidiploid,with 2n=48=14M+12m+18sm+4st. In addition,the chromosomal basic numbers and multiple and SAT-chromosomes in the experimental materials are discussed briefly.