Thirty maxillary second premolars were fixed, decalcified, washed and embedded in celloidin to observe the root canal size and morphology at apical 5mm area. The results were as follows: 1. Single canaled teeth and two canaled teeth were approximately equal numbered. 2. Single canaled teeth have round canal but two canaled teeth have long, slender buccal canal and ovoid lingual canal. 3. The canal size of single canaled teeth was $380{pm}30{mu}m,;340{pm}22{mu}m$, but that of buccal canal of two canaled teeth was $360{pm}32{mu}m,;240{pm}28{mu}m$, lingual canal was $330{pm}28{mu}m,;280{pm}20{mu}m$.