eng Ansari Education and Research Society Journal of Ultra Scientist of Physical Sciences April, 2017 29 4 156 163 http://dx.doi.org/10.22147/jusps-A/290404 789 article ALI E.M. SAEED (alikeria_math@yahoo.co.uk) 1 Department of Mathematics, Alzaem Alazhari University, Sudan <p style="text-align:justify">In this paper we investigate the complete FitzHugh-Nagumo System with I  0 . Based on the result in1,2 we discuss the non-existence of homoclinic orbits of the system. Further, we prove that the system has unique limit cycle under the conditions of existence of homoclinic orbits.<br /> &nbsp;</p> https://www.ultrascientist.org/paper/789/ Li euf0a2nard equation FitzHugh-Nagumo System Limit cycle Homoclinic orbits