Developmental dyscalculia (DC) is a primary cognitive disorder of childhood manifested by disturbance of arithmetic ability. As an isolated learning disability (LD), it is usually treated by remedial education and not referred for further medical evaluation. We examined a group of 7 third-grade children with DC attending a mainstream school who had not progressed academically in spite of specific special education intervention. We were able to identify in all 7 children neurological conditions that had direct bearing on the children's cognitive disabilities and remedial programs. One child had petit mal seizures, another developmental Gerstmann syndrome, a third had dyslexia for numbers, and 4 children had attention deficit disorders without hyperactivity. Based on this experience, we suggest that the indications for medical or neurological assessment be broadened to include children who are not improving academically in spite of appropriate professional intervention.