To determine the prevalence of dental caries and oral health behaviors in a sample of the Portuguese army. Methods: An observational cross-sectional study was conducted in a sample of army soldiers of the Infantry Regiment no. 14 of Viseu, Portugal, using a questionnaire. The study involved 122 members of the armed forces, who were asked to complete a questionnaire autonomously. The questionnaire enquired about general oral-health behaviors but focused mainly on: i) frequency of toothbrushing, ii) use of dental floss and iii) frequency of dental appointments. It also asked about sociodemographic information, like age and gender. An intra-oral observation was also conducted to determine the DMFT index and to record dental plaque based on the Silness and Löe plaque index (1964). Results: The prevalence of dental caries was high (51.6%±7.4%; DMFT of 4.6±3.5). The most prevalent score of the Silness and Löe plaque index was score 2-visible plaque (58.2%). Regarding oral hygiene habits, most of the sample reported brushing their teeth at least twice a day (65.6%) and using fluoride toothpaste (64.8%). However, very few participants (18%) used dental floss. More than 30% of the participants had not visited a dentist within the previous year. Furthermore, 45.9% were current smokers. Conclusion: Prevention programs and promoting actions for oral health with these specific groups are important and should be adopted to reduce the prevalence of dental caries and to increases the knowledge about oral-health behaviors. (Rev Port Estomatol Med Dent Cir