This research study compared learning of 6-9th grade deaf students under two modes of educational delivery--interpreted vs. direct instruction using science lessons. Nineteen deaf students participated in the study in which they were taught six science lessons in American Sign Language. In one condition, the lessons were taught by a hearing teacher in English and were translated in ASL via a professional and certified interpreter. In the second condition, the lessons were taught to the students in ASL by a deaf teacher. All students saw three lessons delivered via an interpreter and three different lessons in direct ASL; the order of delivery of each presentation was counter balanced between the two groups of students. Following the instruction, each group was tested on the science lecture materials with thirty-six comprehension questions. Results indicated that deaf students who received direct instruction in ASL from the deaf teacher scored higher on content knowledge.