OBJECTIVE: The purpose of this study is to evaluate the effects of cold air application on the pressure threshold of myofascial trigger points. METHOD: The 60 patients with myofascial trigger points in unilateral infraspinatus muscle were divided into 3 groups with equal number and cold air was applied using CRAis (Kyung-won Century, Korea) for 1, 3 and 5 minutes. We examined the changes of pressure threshold in myofascial trigger points before, immediately after and 30 minutes after cold air application. Also we examined the changes of pressure threshold of contralateral infraspinatus muscles. RESULTS: 1) The pressure threshold of trigger point in infraspinatus muscle were increased immediately and 30 minutes after the cold air application as assessed by the pressure algometer (p<0.05). 2) There was no significant correlations in the changes of pressure threshold among 3 groups after the cold air application (p>0.05). 3) There was no significant correlations among the age, the body mass index and the changes of pressure threshold in myofascial trigger points (p>0.05). CONCLUSION: We conclude that the cold air application is a effective method for treatment of myofascial trigger points.