Abstract : One of the main reasons for patients to seek orthodontic treatment is esthetic or cosmetic causes. The midline is an essential reference for all esthetic deviations. So, knowledge of the midline will result in an improved understanding of facial and dental esthetics invariably. However, there is numerous methods for determine facial midline, the present study had been established to find the relationship between the facial midline and dental midline in two different methods and compare the results of the two methods. The objective of the present study were to assess the prevalence of facial and maxillary dental midline coincidence and non-coincidence by frontal digital photograph and clinical dental floss examination, assess the distribution of midline coincidence and non-coincidence regarding gender and side, and compare between the result of frontal digital photograph and dental floss examination regarding coincidence and non-coincidence. The sample consist of 110 Iraqi adults (60 females, 50 males) aged 18-25 years. Clinical examination by a digital photograph and dental floss were performed for each individual to determine facial midline. Frontal full-face digital photographs of the subjects (in smile) were made under standardized conditions using a digital mobile camera. Imaging software was used to mark the dental midline and to digitally constructing an Esthetic frame, which was used to mark the facial midline. Also, the facial midline determined clinically by stretching a dental floss from the nation to pogonion passing over the midline of the philtrum to see the correlation with dental midline which represents the vertical line through the tip of the incisal embrasure between the two maxillary central incisors. The results of the present study showed that the non-coincidence of facial and maxillary dental midline results contribute the highest percentage (60%), (51.81%) by photographic analysis and dental floss examination respectively. Maxillary dental midline shift to the right side in the majority of the sample (65.15%), (61.40%) by photographic analysis and dental floss examination respectively. For males and females, the facial midline non-coincidence with maxillary dental midline and shift to the right side in the majority of the sample by both methods. There is no significant difference between the results of photographic analysis and dental floss examination. Facial midline not a coincidence with the maxillary dental midline in the majority of the sample by both methods frontal photograph and dental floss assessment. For male and female, the facial midline non-coincidence with maxillary dental midline and shift to the right side in the majority of the sample by both methods, and there is no significant difference between the frontal photograph and dental floss methods