The present study examines the use of protocol analysis as a technique for assessing the difficulties experienced by students with mild disabilities in arithmetic word problems. Thirty-one students classified as learning disabled or behavior disordered, ages 8 to 14 participated in the study. Students were presented arithmetic word problems which were constructed according to a specific matrix. Some of the problems required classification of information and some required the students to deal with extraneous information. All four arithmetic operations were represented. Students were presented problems in individual sessions with one examiner conducting the assessment and a second examiner recording all the students' behaviors and verbalizations in a narrative record. A narrative protocol was thus developed for each student as they engaged in solving the problems. The protocols were then analyzed to determine the cognitive processing difficulties of students and formulate recommendations for teachers working with mildly disabled students. The utility of protocol analysis as a diagnostic tool is discussed, as well as other possible applications of the technique.