This study aimed to investigate and compare advisor and students opinions toward characteristics of undergraduate student advisors in Rajamangala Institute of Technology by two aspects : personality and responsibility. The subjects consisted of 641 advisors and undergraduate students in the second semester, 1992. Rating scale questionnaires with 57 items were mailed and 96.10% were returned. Statistics used for analyzing data were mean, standard diviation and t-test. Major findings were as follows: 1. Advisors opinion toward characteristics of undergraduate student advisors was at the high level. When considered each of the two aspects, it was found that personality of the advisors was rated at the high level while responsibility was rated at the moderate level. The undergraduate students opinion towards characteristics of undergraduate student advisors was at the moderate level. When considered each of the two aspects, it was found that they were also rated at the moderate level. 2. The opinions of advisors and undergraduate students relating characteristics of undergraduate student advisors were significantly different at the 0.01 level. When considered each of the two aspects, it was found that there was significant difference at the 0.01 level in the opinions of advisors and students toward characteristics of undergraduate student advisors both of the two aspects.