Purpose <p>Incisional hernias reflect a common complication after abdominal surgery. Main treatment consists of defect closure and mesh insertion using the sublay method. The aim of the present study was to assess the association of mesh fixation to patients’ outcome.</p> Methods <p>Using the Herniamed registry, data from 13’452 incisional hernia repairs were analyzed retrospectively. Three groups of patients were compared: those with mesh fixation (<i>n</i> = 9’986), those with self-fixing meshes (<i>n</i> = 2’725), and those without mesh fixation (<i>n</i> = 741). Postoperative complications, recurrence and postoperative pain scores were assessed over a follow-up period of one year postoperatively.</p> Results <p>Taking into account that patients without mesh fixation had smaller defects and were treated with smaller meshes indicating non-equivalent groups, postoperative complications (general, intra- and postoperative complications, as well as complication-related reoperations), were similar among groups except that self-fixing meshes showed a lower general complication rate compared to fixed meshes (OR = 0.733 [0.579; 0.929]; <i>p</i> = 0.010). Mesh fixation had no relation to recurrence rate. Self-fixating meshes were associated with increased pain at rest rate (OR = 1.325 [1.156; 1.518]; <i>p</i> &lt; 0.001), pain on exertion rate (OR = 1.255 [1.125; 1.400], <i>p</i> &lt; 0.001) and chronic pain requiring treatment (OR = 1.271 [1.086; 1.488], <i>p</i> = 0.003) compared to fixed meshes. Self-fixating (OR = 1.675 [1.322; 2.120], <i>p</i> &lt; 0.001) and fixed meshes (OR = 1.334 [1.069; 1.666], <i>p</i> = 0.011) were associated to increased pain on exertion rate compared to non-fixed meshes.</p> Conclusion <p>It appears that mesh fixation can be omitted during sublay incisional hernia repair.</p>