Developmental learning difficulties are among the prevalent exceptionalities school learners have today. In this regard, identification and placement are among the facilitators of later successful intervention for these groups of learners (WestOlatunji, Shure, Pringle, Adams, Lewis & Cholewa, 2010). However, there are not enough resources such as tools to measure the learners' difficulties (Alim, Abdallah, Ramaroson, Sidikou & Van de Wiel, 2007) available. The tools, which objectively help a professional to identify a learner's level of difficulty is an essential resource, however, they are scarce. With this study we aimed to develop an observation card to determine the prevalence of developmental learning difficulties among primary school students in Sana'a City, Yemen. A 24-item tool was used and analysed to test its psychometric properties. A total of 238 students with ages ranging from 6 to 13 years participated in the study. The findings of the study suggest the final formulation of the items to be included in the observation card that can measure the prevalence of this exceptionality through the use of observation scores. The observed raw score had been standardised by its deviation from the sample's mean. Further, the findings reveal that there were statistically significant differences in the respondents' level of difficulties in terms of their gender and grade. Recommendations of the study are presented in this article.