Background: Identification of sex and ethnicity has always been a challenge in the field of forensic medicine and criminal investigations. Fingerprinting and DNA comparisons are probably the most common techniques used in this context. However, since they cannot always be used, it is necessary to apply different and less known techniques such as lip prints. The objective of this study is to determine predominant lip print pattern found among population of Siwan district of Bihar (India) and to evaluate whether any sex difference exists. Materials and methods: To accomplish the proposed objectives of the study a total 110 volunteers (55 males and 55 females) were recruited and the lip prints were collected on a white bond paper. Each lip print was divided into four compartments and were classified and scored according to Suzuki and Tsuchihashi classification. Data were statistically analyzed. Results: The results showed that the overall, Type II (Branched) was the most frequently observed and Type V (Undetermined) was least frequently observed pattern in the examined subjects of the Siwan (Bihar) population in India. Type II (Branched) lip print pattern was found to be most commonly found in both sexes i.e., males and females. In male lip prints, the order of appearance of patterns were Type II > Type I’ >Type III> Type I> Type IV > Type V (least common) and in female lip prints, the order of appearance of patterns were Type II> Type I’> Type IV> Type III > Type I> Type V (least common). Conclusion: This study contributed to the cheiloscopic characterization of an Indian sample and, despite the results of the present study, does not prove that sex determination through cheiloscopy is perfect. It is established that there is no similarity of lip prints from one individual to another individual and between males and females.