Purpose: Observe clinical features of congenital Fourth nerve palsy in NHP from 1/2011 to 12/2013. Methods: Retrospective chart review of 45 patients with congenital superior oblique palsy. All patients had a completed eye examination: diplopia vertical, hypertropia, abnormal head posture, head tilt toward, underaction of the superior oblique muscle, overaction of antagonistic inferior oblique muscle. Three steep Test of Pack, Bielschowsky Test for diagnosis. Results: 20 Male and 25 Female, 100 percent fourth cranical nerve in unilateral. 100 percent patients with hypertropia, 100 percent patients without diplopia vertical. 100 percent patients with underaction superior oblique muscle. 100 percent patients with head tilt (abnormal head posture). Overaction inferior oblique muscle in 100 percent. 80 percent patients with facial asymmetry.