The aim of this study was to assess the clinical efficacy of a new reading intervention program, Understanding Words, for struggling readers in an open trial design. Twenty-five participants who had poor reading skills and typically had a mix of coexisting developmental disorders completed the 40-hr program over 20 weeks. Significant gains were achieved on measures of word identification, phonological decoding, and reading comprehension. Growth in reading ability per hour of intervention matched the average reported in the literature. Individual analysis showed that 84% of the sample returned to the average range on a measure of phonological decoding and 52% to 56% achieved the same gains in reading comprehension. Limitations of study design and future research directions are also discussed.