This paper presents an effectiveness study of a computer-based English reading program, the Waterford Early Reading Program (WERP), among first and second grade students in Israel. Students who used the program were compared to a control group only receiving English as a foreign language (EFL) instruction as part of the school curriculum. First grade students who used the software during the study period experienced significantly greater gains than control group students on all four measures of reading ability. Second grade students in the treatment group experienced greater gains than control group students on the nonsense word and phoneme segmentation measures. These results indicate that adaptive English reading software has a place in an EFL education system, especially among young students with complex linguistic backgrounds. Adaptive programs like WERP may produce better EFL results than non-adaptive programs because they are able to adjust based in part on a student's linguistic proficiency. (Contains 2 tables and 1 note.)