PURPOSE: To evaluate the clinical utility of the teleradiology system using the information super highway communication network. MATERIALS AND METHODS: Two radiologists selected 101 cases of pneumothorax and 20 cases ofmiliary tuberculosis. There were scanned and transmitted to our hospital at a speed of 640 Kbps and displayed on avideo monitor with a resolution of 1280 pixels/line x 1024 lines. Four radiologists divided into three groups :read the images group A read the images without image processing ; group B read the images with image processing, group C read the radiographic films on the view box. The authors compared sensitivity and specificity between thegroups and checked their statistical significance using the Chi-square test. According to the location of thepleural line, we divided the pneumothorax into four types : continve on this live type 1, pleural line confined tothe apex ; type 2, to the upper half ; type 3, to the lower half ; type 4, to the upper through lower half. We then compared sensitivity between the Three groups. RESULTS: In the pneumothorax group, the average sensitivity of group A, B and C was 79%, 90% and 96%, and average specificity was 99%, 99% and 94%, respectively. There were statistically significant differences in seasitivity between group A and B and between group B and C (p<0.017). There were no statistically significant difference in specificity between group A and B or between group B and C.In the miliary tuberculosis group, the average sensitivity of group A, B and C was 73%, 78% and 90%, and average specificity was 95%, 95% and 100%, respectively. With regard to sensitivity and specificity, there was no statistically significant difference between group A and B or between group B and C but there was a statistically significant difference between group A and C (p<0.017). According to the location of the pneumothorax, for alltypes, the sensitivity of group A was less than that of group B and group B was less than that of group C. CONCLUSION: All groups showed reduced observer performance in the detection of pneumothorax and miliary tuberculosis when reading a transmitted image on the monitor-workstation compared with reading conventional radiographs on the view box. To improve the clinical utility of the teleradiology system, a higher resolution workstation and adequate image processing are required.