Objective: The quality of dental cases scenario is an important factor in the success of Problem Based Learning (PBL) method. High quality scenario cases connect between the scientific knowledge with the real problems or show the clear connection with the profession in the future, so that it will increase the student motivation. The good case should be able to be a trigger for self directed learning, and in line with the prior knowledge of students, it will enhance the problem solving and can stimulate group dynamics. Scenario cases were supposed to be written very carefully to avoid bias and to be able to reflect the expecting purpose of the study. The aim of this study was evaluate the quality of cases that have already used at small group discussion in the first block of PBL blocks year 1 – 4, in academic year 2013 - 2014 at dental school of UMY. Method: Questionnaires were used to assess the student perception towards quality of the cases scenario during small group discussion in block 1, 7, 13, and 19. Questionnaires were divided into 18 items, including 6 aspects that have to be involved in each scenario cases. Good PBL cases comprise of thinking stimulation, logical analysis (3 items) stimulate independent learning (3 items), encourage to learn about targeted content (3 items), increasing the interest toward learning materials (3 items), relevance of the future profession and real context (3 items), and the compatibility with previous knowledge level (3 items). Twelve cases were evaluated by student. All items are assessed using 5 points of Likert scale after being discussed. Students were told to indicate the item relevance level in each case (scale 1= strongly disagree to scale 5 = strongly agree) Result: Total student that involved in this study were 404 students (first year student: 110 students, second year: 109 students, third year: 88 students, and fourth year: 97 students). The results of descriptive statistics per item in 12 scenario with N=110 show that the mean score and standard deviation is in the range mean of =3.14, SD = 0,8, to mean of 4,07,SD = 0.7, The highest mean score was at items 5 and 13 (mean =3.8). Overall no items were rated as insufficient (a mean score below 3.0) in all cases scenario. There are four cases scenario that need more attention and improvement at the several aspects of the scenario (means score more than 3 to 3.5). Conclusion: It can be concluded that scenario cases in the first blocks at academic year of 2013 to 2014 in dental school of UMY already have good quality but still need improvement in some aspects to meet the criteria of a good PBL case scenario. Key words : cases, PBL, and quality