Background: Humeral shaft fracture accounts for approximately 3% of all the types of fractures and is the most common type of fracture occurring in adults. A surgical intervention for a humeral shaft fracture is controversial whether as to intervene or not but for other types of fractures like multiple fractures, severely displaced fractures, a comminuted fracture and fractures where there is vascular and nerve injury surgical intervention is definitely required. Aim: Outcomes of comparison between I/M interlocking nail and plating in fractures of humerus shaft in adult patients. Methodology: A randomized clinical trial was conducted at the Department of Orthopedic Surgery, Sh. Zayed Hospital, Lahore over a period of six months. 190 patients (divided in two equal groups by lottery method) were included. Informed consent was taken. Demographics like age, gender, duration of fracture were obtained. In group A patients underwent surgery by using IMN fixation. In group B, patients underwent surgery by using plate. Patients were followed-up in OPD of 10 days. Then patients were followed-up further in OPD for 24 weeks. If union achieved in 24 weeks, then success was labeled. Results: Total of 190 patients, mean age was calculated as 39.57 +/- 8.09 years in group A and 40.01 +/- 8.79 years in group B. There were 62(32.6%) males whereas 48(25.3%) were females in group A and that 63(33.2%) were male whereas 32(16.8%) were females in group B. Frequency of success was 94(49.5%) in group A and 92(49.4%, in group B. Frequency of infection was 1(0.5%) in group A and 2(1.1%) in group B Conclusion: It is concluded that there was no significant difference in both groups. Intramedullary nail and plate provides good outcome with no complications in the treatment of humerus shaft fractures.