Background: Oral carcinoma is one of the common types of cancer and one of the 10 leading causes of death around the world. This study was conducted to evaluate senior dental student knowledge about oral cancerous lesions in Zahedan Dental School. Materials and Methods: In this cross-sectional research, all the students in the last academic year at the School of Dentistry were studied during year of 2013. The study questionnaire covered demographic data as well as 12 questions concerning the knowledge of oral cancer. Data were collected and analyzed with SPSS18 using independent t-test, one way ANOVA. Significance level was considered as $p{leq}0.05$. Results: Of the 104 senior dental students, with an average age of $27.34{pm}7.79$ years, who participated in this study, 32 (30.8%) were female and 72 (69.2%) were male. The mean score of the students regarding the knowledge of oral cancer was $7.24{pm}2.61.20$ students (19.2%) had a weak knowledge, 45 students (43.3%) had a moderate knowledge, and 39 students (37.5%) had a good knowledge. Conclusions: The student knowledge of oral cancer is not satisfactory and they need to receive additional information and education.