Background: Dietary assessment is a challenge in general, and specifically in individuals with intellectual disabilities (ID). This study aimed to evaluate personal digital photography as a method of assessing different aspects of dietary quality in this target group. Method: Eighteen adults with ID were recruited from community residences and activity centres in Stockholm County. Participants were instructed to photograph all foods and beverages consumed during 1 day, while observed. Photographs were coded by two raters. Observations and photographs of meal frequency, intake occasions of four specific food and beverage items, meal quality and dietary diversity were compared. Evaluation of inter-rater reliability and validity of the method was performed by intra-class correlation analysis. Results: With reminders from staff, 85% of all observed eating or drinking occasions were photographed. The inter-rater reliability was excellent for all assessed variables (ICC greater than or equal to 0.88), except for meal quality where ICC was 0.66. The correlations between items assessed in photos and observations were strong to almost perfect with ICC values ranging from 0.71 to 0.92 and all were statistically significant. Conclusion: Personal digital photography appears to be a feasible, reliable and valid method for assessing dietary quality in people with mild to moderate ID, who have daily staff support.