Abstract : Badly broken primary anterior teeth present higher risk of failure due to loss of tooth structure. The aim of this study is to assess the fracture resistance of upper primary anterior teeth restored with fiber posts after Al2O3 sandblasting, 9% hydrofluoric acid and Er,Cr:YSGG laser (2790 nm) surface pretreatments. Sixty fiber posts were used and randomly divided into 4 groups: Group I: control (no pretreatment), Group II: sandblasting (Al2O3) pretreated post, Group III: 9% hydrofluoric acid etching pretreated post, Group IV: Er,Cr:YSGG laser (2790 nm) pretreated post which was further subdivided into subgroup A: 0.5W, subgroup B: 1W, subgroup C: 1.5W. Sixty extracted primary maxillary anterior teeth were collected. After pulpectomy roots were filled with Metapex then surface treated fiber post were cemented with resin cement. Fracture resistance was measured using universal testing machine at a cross head speed of 0.5mm/min. Each sample was loaded at 135º along the long axis of the teeth on the mid-palatal surface until fracture. One-way ANOVA followed by Tukey post hoc test was used to compare between more than two groups in non-related samples. Results revealed a statistically significant difference between the control and all the treated groups except for Group II (p=0.868). Subgroup B had the highest mean fracture resistance value (370 N +/-43.97) while Group III showed the lowest mean value (111.78 N ±16.97). Surface treatments with Er,Cr:YSGG (2790 nm) 1W is an effective method for improving the fracture resistance of badly broken primary anterior teeth restored with fiber post.