Sudden birth of entanglement between two initially separate atoms interacting with two entangled photons in a double JC model is investigated, and the influences of different atomic initial states on entanglement among atoms are discussed. The results show that sudden birth of entanglement can occur when the two atoms are initially in excited states.OCIS code: 270.0270.doi: 10.3788/COL20090705.0443.This work was supported by the National Natural Science Foundation of China (No. 10374025) and the Education Ministry of Hunan Province (No. 06A038).1. A. Einstein, B. Podolsky, and N. Rosen, Phys. Rev. 47, 777 (1935).2. A. K. Ekert, Phys. Rev. Lett. 67, 661 (1991).3. C. H. Bennett, G. Brassard, C. Crépeau, R. Jozsa, A. Peres, and W. K. Wootters, Phys. Rev. Lett. 70, 1895 (1993).4. J. I. Cirac and P. Zoller, Phys. Rev. Lett. 74, 4091 (1995).5. I. Sainz, A. B. Klimov, and L. Roa, Phys. Rev. A 73, 032303 (2006).6. M. Franca Santos, P. Milman, L. Davidovich, and N. Zagury, Phys. Rev. A 73, 040305(R) (2006).7. Z. Ficek and R. Tanas, Phys. Rev. A 74, 024304 (2006).8. J. Qian, X. Feng, and S. Gong, Chin. Opt. Lett. 5, 484 (2007).9. Y.-H. Hu, M.-F. Fang, C.-L. Jiang, and K. Zeng, Chin. Phys. B 17, 1784 (2008).10. T. Yu and J. H. Eberly, Phys. Rev. Lett. 93, 140404 (2004).11. T. Yu and J. H. Eberly, Phys. Rev. Lett. 97, 140403 (2006).12. G.-F. Zhang and Z.-Y. Chen, Opt. Commun. 275, 274 (2007).13. G.-F. Zhang, Chin. Phys. 16, 1855 (2007).14. Q. Yang, M. Yang, and Z.-L. Cao, Chin. Phys. Lett. 25, 825 (2008).15. N. Metwally, Int. J. Theor. Phys. 47, 623 (2008).16. M. P. Almeida, F. de Melo, M. Hor-Meyll, A. Salles, S. P. Walborn, P. H. Souto Ribeiro, and L. Davidovich, Science 316, 579 (2007).17. J. Laurat, K. S. Choi, H. Deng, C. W. Chou, and H. J. Kimble, Phys. Rev. Lett. 99, 180504 (2007).18. L. Mazzola, S. Maniscalco, J. Piilo, K.-A. Suominen, and B. M. Garraway, quant-ph 0812.3546, (2008).19. Z. Ficek and R. Tanas, Phys. Rev. A 77, 054301 (2008).20. C. E. López, G. Romero, F. Lastra, E. Solano, and J. C. Retamal, Phys. Rev. Lett. 101, 080503 (2008).