ABSTRACT Objective: Anal fissure is a common problem through the world, it causes considerable morbidity. The aim of the study was to evaluate the effect of designed nursing guidelines on acute anal fissure treatment outcomes. Methods: Research design: Quasi-experimental design. Setting: General Surgery Wards and Outpatient Clinics of General Surgery at Assiut University Hospital. Sample: A purposive sample of 60 male and female adult patients diagnosed of having acute anal fissure. Patients were equally divided on random basis into two equal groups (study and control) 30 patients for each. Tools: Tool I-Patient assessment sheet. Tool II-Numeric Pain Rating Scale. Tool III-Bates-Jensen Wound Assessment Tool. Results: No statistically significant difference was found between the study and the control groups as regard demographic data. There was a statistically significant improvement in the pain level and wound healing among the study group (1.63 ± 2.08 and 11.93 ± 4.5 respectively) than in the control group (2.87 ± 2.33 and 14.43 ± 4.29 respectively). Also, there was a high statistically significant improvement in the level of knowledge of the study group than their level before applying the guidelines (p .001). Conclusions: Designed nursing guidelines had a statistically significant effect on improving patients’ knowledge, pain level, and wound healing among the study group patients than among the control group ones with acute anal fissure. Recommendations: Patients teaching should be an integral part of the nurses’ duty in all hospitals. Further studies on larger sample from different geographical areas in Egypt to generalize the results.