Purpose: To examine the effects of the hemostatic agents ViscoStat and ViscoStat Plus on the shear bond strength (SBS) of composite resin (CR) to dentin in the presence and absence of blood. Materials and Methods: Sixty permanent teeth mounted in acrylic were randomly divided into 5 groups (n = 12): (1) control, C; (2) ViscoStat, VS; (3) ViscoStat Plus, VS+; (4) ViscoStat and blood, VS/B; (5) ViscoStat Plus and blood, VS+/B. Groups 2 and 3 were exposed to VS and VS+, respectively. Freshly drawn human blood was placed on groups 4 and 5 immediately followed by VS and VS+, respectively. Specimens remained undisturbed for 1 min and were rinsed with tap water for 1 min. All groups were etched with 35% phosphoric acid and were bonded utilizing the Ultradent bonding clamp, Optibond Solo Plus, and Z-250 composite resin. Following water storage for 48 hrs at 37°C, specimens were debonded in an Instron test frame at a crosshead speed of 0.5 mm/min. Statistical analysis was done with one-way analysis of variance. Results: The mean SBS ± SD in MPa were C: 44.2 ± 4.8, VS: 42.3 ± 8.7, VS+: 46.2 ± 7.8, VS/B: 43.0 ± 6.4, VS+/B: 44.0 ± 8.1. ANOVA revealed no significant difference (p > 0.05) between SBS of VS or VS+ and the control with or without blood present. Conclusion: This controlled laboratory study concluded that the use of ViscoStat or ViscoStat Plus as a hemostatic agent does not have a significant effect on the shear bond strength of composite resin to dentin when using Optibond Solo Plus. Schlagwörter: ViscoStat, ViscoStat Plus, shear bond strength, composite resin contamination