Background: The Ethiopian national strategy for the prevention, control and elimination of malaria is one of the Health Development Programs (HDP IV). Dengue fever is one of the vector borne diseases that causes Acute Febrile Illness and death in tropical and sub-tropical countries. Knowledge, attitude and practice of health-care professionals towards dengue fever prevention and associated factors among health professionals is not yet well known across the country and concern is varied in context and place. Therefore, the aim of this research was to assess knowledge, attitude and practice towards dengue fever prevention and associated factors among public health sector health-care professionals in Dire Dawa administrative city, eastern Ethiopia. Materials and methods: An Institution-based cross sectional study was conducted from September 9 to October 13, 2017. The study was conducted among a sample of 348 health-care professionals which were from the randomly selected nine clusters of public health facilities located in urban and rural areas of Dire Dawa. Data were collected by self-administered structured questionnaire. Bivariate and multinomial logistic regression analyses were made to check the associations among predictor variables and to control for confounding factors. A P -value <0.05 was used to declare statistical significance. Results: Of the 348 sampled health-care professionals, 300 were included in the analysis giving a response rate of 86.2%. Nearly half (148/49.3%) of the participants demonstrated a moderate level of knowledge, 140 (46.7%) a neutral level of attitude and 156 (52%) a low level of practice towards dengue fever prevention. Multinomial logistic regression revealed that type of health profession, type of health facility and dengue fever prevention training status were significantly associated with the knowledge, attitude and practice of health-care professionals. The odds of physicians and public-health officers having a high level of knowledge or a low knowledge level were (AOR [95% CI] =38.793 [7.279, 206.734]) and (AOR[95% CI] =6.15[1.643, 23.026]) times higher than the odds for nurse professionals. The odds for professionals who worked in health centers and had a high knowledge level towards dengue fever prevention were (AOR [95% CI] =0.252 [0.086, 0.737]) times higher than those working in referral hospitals. The odds of health-care professionals who were public-health officers and those who worked in primary hospitals having a favorable attitude towards dengue fever prevention were (AOR [95% CI] =7.011 [1.867, 26.321]) and (AOR [95% CI] =3.683 [1.284, 10.563]) times higher than the odds for nurse professionals and those who worked in a referral hospital setting respectively. The odds of health-care professionals who took dengue fever prevention training were 10.23 times (AOR [95% CI] =10.23 [1.052, 99.478]) higher than the odds for health-care professionals who had not received the training....