Magnesium alloys have been in the focus of research in recent years as degradable biomaterial. The purpose of this study was the biomechanical characterisation of MgCa0.8-screws. The maximum pull out force of screws was determined in a synthetic bone without corrosion and after fixed intervals of corrosion: 24, 48, 72 and 96 h. This in vitro study has been carried out with Hank's solution with a flow rate corresponding to the blood flow in natural bone. A maximum pull out force (F(max)) of 201.5 ± 9.3 N was measured without corrosion. The biomechanical parameter decreased by 30% after 96 h in corrosive medium compared to the non-corrosion group. A maximum load capacity of 28 ± 7.6 N/h was determined. Our biomechanical data suggests that this biodegradable screw provides a promising bone-screw-fixation and has great potential for medical application.