Quantitative description of the value of Picture Archiving and Communication System (PACS) in the health care environment is essential to assess the benefits with which PACS provides us. It is necessary to obtain data related to our film-based system before PACS installation in order to make quantitative comparison of before-and-after PACS operation, so that we can assess the clinical effectiveness brought by the PACS itself. We conducted flow study to acquire the whole chart of data flow related to radiological examination. And then defined the parameters and employed them to conduct time study for measuring several items concerning order entry, report making and image delivery at outpatient clinics and wards of eight departments using stopwatches, IC cards and time-recorders. This paper describes the results of measurement. For example, the location of each clinic/ward affected the time spent for images/reports delivery, and that hand writing time occupies more than half of the time required for making a single diagnostic report in 16 percent of cases. These results indicate that acceptability by medical staff is the key to successful operation of PACS. For instance, simple man-machine interaction at image display workstation must be properly realized. By using the same parameters mentioned above, we can compare those data with the results measured after PACS operation in a few years.