Background : The aim of this study wits to compare the effect of topical glycerol trinitrate ointment (GTN) with topical diltiazem hydrochloride ointment (DTZ) in the treatment of chronic trial fissure Method : Prospectively, 102 patients were treated randomly with either GTN ointment (0.2%) or DTZ ointment (2%) a couple of times daily for 12 weeks Results : Forty-five patients (88.2%) in group DTZ and 36 patients (70.6%) in group GTZ had I reduction of symptoms. The decrease in the symptoms for group DTZ was significantly more than for group GIN (P = 0 02). Mean time for symptom reduction was 2.44 +/- 0.30 in group DTZ and 2.50 +/- 0.28 weeks in group GTN with no significant differences between the two groups (P > 0.05). Complete relief of symptoms was observed in 72.5% and 54.9% patients in groups DTZ and GTN. respectively. The frequency of complete relief of symptoms between the two groups was not significant (P > 0.05) Complete remission of anal fissure occurred in 66.7% patients in group DTZ and 54.9% patients in group GTN, which shows no significant difference. Mean time taken for fissure healing in the GTN group was dramatically less than in the DTZ group (P = 0.001). Finally, 33.3% of patients in the DTZ group and 45.1% of patients in the GTN group underwent operation The need for operation was not significantly different between the two groups (P > 0 05). Conclusion : Both DTZ and GTN are equally effective and can be the preferred first-line treatment of chronic anal fissure However, GTN is associated with,I higher rate of headache, and should be replaced by DTZ.