Purpose: The purpose of this study was to analyze the effectiveness of saline solution vs. heparinized-saline for maintenance of arterial lines and to detect changes in platelet and aPTT as physiological indexes. Methods: In this nonequivalent control group, non-synchronized, double-blind study the effects of heparinized and saline solution on the maintenance of arterial lines were compared. Fifty five patients received the heparinized solution and fifty nine patients received the saline solution. All patients who had surgery in K-university hospital between September and December 2011 were eligible for participation in the study. Results: There was no statistically significant difference between the saline and the heparin group in the maintenance time of the arterial lines or the number of irrigations. There was no statistically significant difference between the groups in changes in the number of platelets and aPTT for interaction between the groups and time intervals. Conclusion: The results indicate that saline solution can be used as an irrigation solution for the maintenance of arterial lines of adult surgical patients, rather than heparinized-saline, in view of potential risk factors in the use of heparin.