The objective of this study is to assess the effectiveness and safety of onlay mesh closure of emergency midline laparotomy to prevent incisional hernia. This is a prospective randomized double-blind study and was carried out in the General Surgery Clinic, Konya City Hospital, from August 1, 2020 to August, 1, 2021. The study included 108 patients who were randomly grouped in 2 groups: patients with conventional abdominal closure and closure using additional onlay mesh (1:1). The follow-up period was for a year. The primary outcome was the incidence of incisional hernia and secondary outcomes were clinical data like complications, hospital length of stay, re-operations. It was observed that incisional hernia was present in 14 patients (27.4%) in conventional abdominal closure group and was in 2 patients using mesh (4%), (p = 0.001). Clavien-Dindo 3B complications were in rise in conventional closure group (p = 0.02). Of all complications, burst abdomen was significantly more common in conventional closure group (p = 0.04). The rate of surgically treated complications were higher in conventional closure group (p = 0.02). Clavien-Dindo 3A complications were more common in patients with contaminated wound in mesh group (p = 0.02). The use of mesh while closing the abdomen in emergency midline laparotomy reduces the risk of incisional hernia. Thus, to lower the risks of incisional hernia and its complications, prophylactic mesh can be used in high-risk patients.