Purpose : To evaluate the magnification error percentage in repeatedly taken panoramic radiographs of same patient and machine. Materials and Methods : 92 panoramic radiographs from 46 patients were traced and 30 horizontal and vertical measurements were made with digital sliding caliper. The results were compared with paired t-test. Results : There was no statistically significant difference between the two measurements. The overall difference as percentage error was $6.19pm5.60\%$. The largest error as $14.61pm12.44\%$ was found at condylar height 1, and smallest as $1.86pm1.61\%$ at mandibular height. Overall vertical error excluding condylar height 1 was $3.76pm3.97\%$, and the horizontal error $6.88pm5.92\%$. Conclusion . Repeatedly taken panoramic radiographs of the same patient and machine was reliable since there was no significant percentage error difference but the percentage error ranged from $1.86pm1.61\%;to;14.61pm12.44\%$ indicating the error depends on the measuring site.