Repairing teeth without coronal walls after endodontic therapy is challenging, requiring intra-radicular supports. Different post types with varying elastic moduli exist, but there is a lack of trials comparing their effectiveness. Tooth placement is not a significant factor in failure rates. Aim: To compare the performance of glass fiber posts to cast metal posts in teeth without ferrules. Methods: A retrospective study in a dental clinic in North Riyadh examined 280 medical histories of patients needing intra-radicular posts. Criteria included good oral health, limited coronal support, and absence of caries and periodontal disease. Criteria assessed included secondary caries, apical periodontitis, crown fractures, and post debonding. Success was defined as avoiding absolute and relative failures. Results: Demographics showed no significant differences between the two groups. Cast metal posts were significantly more prevalent in the maxillary incisor area, while glass fiber posts were more prevalent in the maxillary premolar area. The glass fiber group had a longer average time until failure compared to the cast metal group. Failure causes did not significantly differ between the groups. Conclusion: Both glass fiber and cast metal posts demonstrated comparable clinical performance. However, glass fiber posts had a longer average time until failure compared to cast metal posts. The choice of post material may impact the timing of failure but not specific failure causes.