Objectives: The aim of this study was to evaluate the influence of two different perfusion solutions (saline, undiluted human plasma) on microtensile bond strength of four different dentin adhesives (Futurabond NR, Clearfil SE Bond, Xeno III, iBond) in vitro. Methods: 120 freshly extracted molars were included. All teeth were specially prepared allowing the simulation of dentin perfusion. The specimens were randomly assigned to eight experimental groups of fifteen samples each. In four groups (AS, BS, CS, DS)saline was used as perfusion solution, in four groups (AP, BP, CP, DP) undiluted human plasma was used. Group AS, AP: Futurabond NR; group BS, BP: Clearfil SE Bond; group CS, CP: Xeno III; group DS, DP: iBond. Microtensile bond strength wasmeasured 15 minutes after light curing of the composite material (Clearfil APX) using an universal testing machine. Results: For the eight test series following tensile bond strengths were evaluated (mean value, standard deviation in MPa): AS 31.57 (± 3.22), AP 45.38 (± 3.87), BS 28.81 (± 3.47), BP 39.44 (± 3.44), CS 23.80 (± 3.59); CP 30.30 (± 3.23); DS 28.62 (± 3.22); DP 46.34 (± 3.24). Statistical analysis showed a significant influence of the used material and perfusion solution on microtensile bond strength (pConclusions: It can be concluded that the use of human plasma results in significantly higher values. Probably the use of human plasma might be a suitable alternative to imitate perfused dentin conditions in testing devices and might eliminate the recognizable discrepancy between different in vitro investigations focusing on bond strength of dentin adhesives. Keywords: dentin bonding agent, dentin, dentin perfusin, bond strength