Novel human embryonal stem cell lines C612 and C910 have been established from hatching blastocytes. Cells were cultivated in mTeST medium on mouse fibroblast feeder-layers. They express common pluripotent markers such as alkaline phosphatase, Oct 3/4, SEEA-4, Nanog, Rex1. Immunophenotyping of these cells by flow cytometry revealed expression of CD90 (Thy-1) and CD117 (c-kit) antigens and weak or no expression of CD13, CD34, CD45, CD130, HLA class I and HLA class II antigens. This pattern of surface antigen expression is common for human embryonic stem cells. G-banding assay of C612 and C910 metaphase plates showed that karyotypic structure of these cells was normal both in chromosome number and structure. The cells are pluripotent because of their capability to generate embryoid bodies, undergo spontaneous differentiation and express markers of all germ layers: nestin, keratin, vimentin (ectoderm), alpha-fetoprotein (entoderm), and muscle alpha-actinin (mesoderm). Thus, C612 and C910 cells have all attributes of typical human embryonic stem cells (diploid, capable of self-renewal, express pluripotent markers and differentiate into three germ layers) and may be of potential use for fundamental and regenerative medicine researches.