To investigate short and long-term outcome after the open preperitoneal flat mesh technique (OPFMT) for umbilical, epigastric, spigelian, small incisional and "port-site" hernia performed as a day case procedure. We retrospectively analyzed records of patients who underwent OPFMT for umbilical, epigastric, Spigelian, small incisional and "port-site" hernia in ambulatory settings between 2004 and 2020 at Clinical Center of Serbia. Demographic and clinical characteristics, operative data and postoperative complications were compared between the groups. Univariate and multivariate analyses were performed to identify predictive factors for mesh infection and recurrence. Overall, 476 patients were divided according to the type of hernia. Early postoperative complications were similar in all study groups. Mesh infection, chronic pain and recurrence were different between groups (p = 0.013, p = 0.019 and p = 0.011, respectively). Overall recurrence rate after OPFMT was 2.5%. Hernia defect, hematoma and length of postoperative stay at the Day Surgery Unit were identified as potential predictors of mesh infection (Odds ratio 6.449, 22.143 and 1.546, respectively; p = 0.027, p = 0.011 and p = 0.038, respectively) while mesh infection was the only potential predictor of recurrence in univariate analysis. Hematoma was an independent predictor of recurrence (Odds ratio 27.068; 95% Confidence interval 2.355-311.073; p = 0.008). The OPFMT performed under local anesthesia as a day case procedure is a safe technique associated with favorable long-term outcome. Hematoma is an independent predictor of mesh infection occurrence.