The aim of this study was to evaluate retentive strengths of three adhesive/resin cement/fiber post systems to the apical third of post-space dentin varying the application method of the luting agent. ENA post (Micerium, Avegno, Genova, Italy), FRC Postec Plus (Ivoclar Vivadent, Schaan, Liechtenstein), and Anatomical Post (Dentalica, Milano, Italy) were luted in prepared root canals using the adhesive system and resin cement provided by the respective manufacturer. Each group was randomly divided into three subgroups (n = 10) according to the technique used to place the luting agent into post space: using a lentulo spiral, applying the cement onto the post surface, and injecting the material with a specific syringe. A push-out test was performed on sections from the post-space apical part of each specimen. All fractured specimens were observed using a stereomicroscope. Bond strength values were not significantly affected by the application technique of the luting agent (p > 0.05). The ENA post system showed the highest retentive strengths. The other two post groups exhibited similar bond strengths to each other. Microscopic analysis revealed a prevalence of post/cement and mixed failures.