The levels of cognitive complexity included by the Ethiopian University Entrance Examination (EUEE) Biology questions are not well explored. The questions included in the examinations need analytical surveying whether they consistently incorporate the levels of cognitive complexity. This study aimed to analyze ten years of EUEE Biology questions according to the Revised Bloom’s Taxonomy of cognitive complexity. Both qualitative and quantitative approaches were employed by the study. The samples were the ten years of Biology Ethiopian University entrance examinations each containing one hundred multiple-choice questions. The data were obtained from the examination papers by using document analysis and then coded into specific patterns according to the levels of cognitive complexity. The coded data were transformed into counts and then quantitative analysis was done by simple descriptive methods; frequency and percentage. Further, the Chi-square test and one-way ANOVA were used to test the distributions of questions among the levels of cognitive complexity and orders of cognitive thinking skills. The results show that the distributions of questions were found to decrease through increasing levels of cognitive complexity. Of the total 1000 questions observed, 468 (46.8%), 366 (36.6%), 59 (5.9%), 56 (5.6%), 30 (3%), and 21 (2.1%) fall under remembering, understanding, applying, analyzing, evaluating, and creating, respectively. The distributions of questions were found 441 (44.1%), 489 (48.9%), 66 (6.6%), and 4 (0.4%) from levels of factual knowledge to meta-cognitive knowledge. Further, the result from the Chi-square test shows that distributions of questions among the levels of cognitive complexity were statistically significant (P < 0.05). Moreover, the distributions of questions were found 834 (83.4%) at lower order cognitive skills, 115 (11.5%) at middle order cognitive skills, and 51 (5.1%) at higher order cognitive skills. The questions among the orders of cognitive thinking skills were significantly different (P<0.05). The results indicate that the examinations incorporated high low level but less high levels of cognitive complexity. On this basis, the levels of cognitive complexity from the RBT should be taken into account when preparing the examination questions.